Not at all. You don't have to identify as yourself on every instance you have an account. It's literally a different account. You can keep a backup of all your subscriptions/follows/etc from one to the other or you can treat them as two entirely different identities. Just don't have them generate a lot of pointless traffic between each other (like arguing with yourself on a post or something).
Depends on the person. The point is, it's entirely up to you. And keep in mind you're not guaranteed to get the same name on every instance you create an account.
What premise? It's not a philosophy. It's an outright technical observation. You can do whatever you want. I didn't say you have to like it. What is there to disagree with? You can say the idea isn't for you, but it's still correct.
That's fucking stupid. I'm done here. Someone in the thread even already posted their two different account names. I guess you think that's just an illusion. Fucking idiot.