You can... at least for now. I don't have it installed on any of my Windows PC's.
I wouldn't put it past them to make it non-uninstallable at some point, like is currently the case with some built in apps like the "Game Bar," an application I totally need to be built into my work PC that doesn't have a dedicated graphics card or any games installed on it.
You can even just sign out and remove it from the startup list.
But people are still going to find ways to fuck around in the registry or use some random Powershell script and then blame Microsoft for “ruining their computer with OneDrive”.
Ironically, these same people often end up paying to get their own files back.