It's politics. Newfound Allies have expectations.
I highly doubt Zelenskyj really wants to get involved with Israels ever ongoing conflict at this point in time.
I'm just pointing out the most likely explanation.
But I have no doubt he's more concerned with own people and that if he wants to keep receiving aid for the war in Ukraine he has to "play ball."
It's a shitty situation to be in.
However I don't think he's going to divert any resources to Israel anytime soon, regardless of the sincerity of his statement. So at least there's that.