<Snipped quote by catchamber>
Not getting into whose wrong or right. But even him being at that place, when it happened wouldn't change that. Most people cannot cover a whole protest or rally 24/7. It would still become anecdotal evidence anyway.
So, you're asking for evidence, that even if he directly gave you. (Like some recording on the event that showed, for as long as he was around and where he was. He still likely could not give you an 100% certainty.) So you wouldn't be satisfied with it. So you shouldn't ask for evidence, if it something that wouldn't effect your opinion about it.
So as @mdk said. It sort of is-getting into an impossible burden of proof fallacy. Whether you believe so or not.
Though just skimming through Warsaw online. I'm getting a shit ton of conflicting stuff in exactly what went down. There was a celebration for Trump's arrival, a fight over an abortion law and apparently this random far right protest too? Poor Poland. <.< *i could be mistaken about this I did say skimmed*
Andreyich could prove that he was there, and that he observed little to no calls for genocide by the people present. I'm not asking for evidence that everyone or no one at the rally acted one way or another. He's claiming to have observed such circumstances, and any evidence that he gathered while there which supports that claim would be appreciated.
TLDR: Why should I believe that Andreyich was there, if he won't prove it?