For him to point out the similarity of being faced with a much large occupier nation than themselves between the position of Ukranians and Palestinians, would pretty much guarantee the end of US military support to Ukraine as the US Congress has several “Friends of other country” groups of parliamentarians (how exactly is being in the parliament of one country defending the interests of a different country not treason?) for various countries, the largest of which is “Friends of Israel” and that group probably controls more than enough members of Congress to stop any future funding of military help to Ukraine.
So yeah, Zelenswky is doing the correct thing in diplomatic terms for his country, unlike many other politicians who don’t act for the good of their own country.
Also lets not forget Hamas is supported by Iran, who has provided drones to Russia to kill Ukranians for over a year now, so yeah, even if he empathises with the plight of Palestinians that’s a whole different thing from agreeing with Hamas.