>inserting himself into their lives at all is disrespectful.

Keep in mind that he's inserting himself into their lives to give them millions of dollars.

Between these two choices:

1) Durov doesn't say anything, insert himself anywhere, or call you anything.

2) Durov gives you millions of dollars, but calls you his child.

I bet my life savings that every single kid will be fine with being called Durov's child in exchange for millions of dollars.

Exactly, even #2 requires child consent with proactive step to prove paternity via DNA test. There's also a third option:

3) Child chooses to ignore inheritance.

What child is going to choose to ignore millions of dollars? But true, that is an option I suppose.

Agreed, it's highly unlikely. But they have a choice, it's not forced by anyone. If they do nothing (maybe their parents never tell them, or they don't read news, or facial recognition never informs them of similarity), there's no inheritance. If they take consensual action to make a claim via DNA paternity test, the inheritance can be claimed.