The biologists that I saw talking about this topic all called it "possible" or "unlikely". Meanwhile the theories that you mentioned are pretty much impossible. "Hitler still being alive somewhere in Argentine" would mean that he is 131 years old.
I think that you let your political affiliations get in the way and cloud your view.
Nobody says that Hitler is still alive. The theory is that he was still alive after the war/was seen in Argentine (i.e he didn't commit suicide) which can be supported/may be "possible".
My point is that without hard evidence anyone can provide "reasonable" arguments for almost anything. That's why we have protocols and run clinical trials instead to rely on what "makes sense"(i.e inject disinfectant to kill covid-19) in our more or less sharp minds.
Now if someone talks bullshit all day long it is very hard to figure out when he says the truth so without evidence it would be safe to assume that whatever he says it is very likely to be false or at least partially false.
I think that you let your political affiliations get in the way and cloud your view.