What's more unsafe - Windows or Android?

It depends purely on the user, his or her knowledge, activities, choices.

That's a weird question, you are comparing a desktop OS with a phone OS (except you are talking about Windows phones, but I don't think you are?).

All it takes to kill your Windows installation is double clicking a random .exe file (and being unlucky that Windows doesn't warn you about this particular file). And nope, if it is a custom program your antivirus won't detect it either. Every time I hear of a company getting a crypto locker on their systems it was over a Windows PC (mostly by email). I haven't heard of your average company getting compromised by a phone yet (but those phones usually don't have network access to shared drives..).

Android is relatively locked down, a lot more than Windows. Even if someone sends you malware per email, there is no easy way to execute it on your phone. It's also not true that you can just install a rogue APK in two clicks, you have to do the following steps:

1. Open the Settings app on your Android device.
2. In the Settings menu, tap Apps.
3. Tap Special app access (or Advanced > Special app access).
4. Tap Install unknown apps.
5. Select an app to use to install an APK file—your browser and file management apps are the best option here.
6. Tap the Allow from this source slider to allow APK files to be installed via that app.

Definitely not something that happens by accident :)

Overall for your average user I'd say Android is safer.

I mean, it literally takes just two taps to install a rogue apk

Unlike Windows programs that get downloaded & installed willy nilly? The Play Store is at least somewhat vetted and by default you can't install third party apps.

All software is unsafe. Leave behind software. Pure hardware is the future.

Hard to tell, but I would say Windows. It’s easier to fool users to download and run arbitrary executable files like ILOVEYOU.txt.exe on a PC. On Android you need to go through many more hoops and turns to run some unverified executable.

Although Windows is pretty well guarded these days.

Purely on equal terms, Windows is more unsafe.

I think it depends on what you mean by safe. Do you mean privacy of personal data or protection against malicious software?

If you mean safe in terms of malicious software, probably Android is safer since there's more vetting with respect to software installation. On Windows the simple act of downloading and opening an exe file can install malicious software. Most Android apps are installed through the store where programs are vetted. It's possible to sideload stuff on Android (download and install an apk), but most people don't go to the trouble. It's not enabled by default and it's not a trivial process to do it.

If you're talking in terms of securing private data, I'd say Windows because there's more control over the data programs can access. Android programs have a lot of access to data on your phone by default and you have to specifically disable it. Windows programs don't have access by default and you have specifically enable it.

If you want to go full paranoid with respect to telemetry, it's much easier to do that with Windows since you have easy access to low level configuration settings through regedit, also the group policy editor. In other words you can configure a Windows machine to disallow any telemetry and MS even provides a guide for it in their online technical documents.

You're making some incorrect assumptions about Android. You can absolutely have company-owned Android phones that are enrolled in management systems that lock things down and only allow pre-approved apps. Same as Windows.

Both platforms allow you to assume your users are stupid and force them to be safe, IF you have ownership of the device. Both are as safe or unsafe as you allow them to be.

Mobile Device Management (MDM) tools have come a LONG way in the past decade and are now very good at thoroughly locking down both iOS and Android devices. Any enterprise wanting to ensure the absolute security of their mobile devices can do so with ease.

At least when it comes to Windows, Administrators have greater control over client machines and can put in restrictions.

This hasn't been true for about 10 years...at least not in the enterprise. Administrators can enforce the same or greater control over client mobile devices using modern Mobile Device Management tools.

How would someone handling infosec in an organization control security on people’s personal phones?

If you take infosec seriously, you aren't going to let your users have access to any corporate data or systems (and that includes email) using their personal devices. If you must, as a compromise, you'll restrict that access only to users of iOS or Samsung devices supporting Knox work profile, and then you'll enable the remote features necessary to monitor and/or wipe everything associated with the work profile in the event the device is lost/stolen or the employee leaves.

I'd say Windows. Android can be more insecure but the Android ecosystem is so fragmented that it's difficult to write malware or exploits that are ubiquitous or even work outside a specific Android ecosystem.

Windows is just kinda a hot mess and has tons of legacy stuff that can be compromised. The attack surface is larger on Windows imo.

If you are to just hand the platform over for a random person to use I feel Android is much less risky. Most people aren't going to go install random apks. Google play store is better than them going off to download random exes even with sketchy apps on there. There's less likely to go wrong on a phone OS. I've never been prompted randomly to download and install a random apk, but I do use Adblock so not sure how frequently using a browser without that on Android would lead to a random person unknowingly downloading then installing an apk after a pop up asks them to.

Androids operating system is pretty locked down, users have restricted abilities to control their own system compared to windows, where most consumers are local admins who can easily run something malicious without realizing it.

By far windows, windows lacks or doesn't fully utilize features like full verified boot, sandboxing which means even if a program installs itself it still has to ask for permission for mic, camera, etc. Adding on to the issues even the programs themselves can be unsafe. Running a program that uses a memory safe programming language is pretty rare and a lot of vulnerabilities come from memory allocation and buffer overflow bugs. Android attempts to mitigate these issues by sandboxing every app, all phones ship with verified boot and full disk encryption, and usually have a memory allocator of sorts. And if you run a degoogled ROM you'll mitigate the privacy issues by not having Google play services installed.

If you need some way to monitor these devices as an admin there are apps on android that allow this functionality, iOS has similar admin features.

edit: typos edit 2: added information

@people_are_cute @nostupidquestions both

Personally I'd say Android because that implies it is running on a phone with a GPS tracker. Even its proper operation feels unsafe to me with constantly sending location data and other data to major corporations.

Both are horrible if you don’t have good remote management.