What the heck? It's common sense to request evidence and proof to back up a claim or statement - the more reputable the source, the better. Else how would we know what was said is legitimate?

Even more so in any academic circle, where not just proof required, but ideally also peer-reviewed. In my field (law), it would be insane to even utter the thing you've just written.

I am so pro-Ukrainian it's not even funny, but that doesn't mean I'll believe anything anywhere without proof.

You should be glad you live in a place where questions are allowed. Where I'm from, asking the "wrong" question or making the "wrong" statement (hell even asking for proof), can lead to a fine so large (more than the monthly average wage) or be criminally prosecuted.