Btw the whole event took place in early December
Where did you get that information? There's a very detailed article about it here.
timesofisrael.com/poland-censors-israeli-mayor-at-official-ceremony-over-mention-of-polish-crimes/
The Israeli Mayor, Dukorsky, says that besides talking about Polish citizens' complicity in actions by the Nazis, he also mentioned the many Poles who saved Jews during World War II.
He says the Polish authorities asked him to omit the number of Jews murdered by Poles during the war, which the speech stated as about 200,000 Jews, and he said he was willing to delete the number.
"But I was requested to make further changes to which I didn't agree," he continued, saying he was asked to substitute the word "Poles" with "Ukrainians" when speaking about Poles' involvement in the Holocaust, and "German Nazis" instead of "Nazis."Has there been any comment from the Polish government or local authorities about it? It would be very odd and foolish for the Israelis to completely fabricate such a story. I really don't think they're that daft.
There is no way a a mayor could demand the contents of a speech and then ban it. There is no mechanism
It's not a question of formal or legal mechanisms. It's a question of informal social interaction. One can
ask, not 'demand' and the person being asked, can be co-operative for the sake of courtesy and observe the formalities of allowing their speech to be glanced over. That would appear to be what happened. The speech can't be 'banned' but the author of the speech can be requested to make changes and if they refuse, the host who invited them to speak is perfectly within their rights to cancel the invitation and equally the speaker is entitled to refuse to deliver the speech.