i think the joke is fine, i think this was an obvious joke too:
(it doesn't seem to be playing, it's trump beating someone up with a cnn logo photoshopped on his face). even in the context of the more adversarial relationship with the press, there are some things which are obvious jokes, and i think both the gif and the biden line qualify.
on not commenting here specifically - maybe, i don't know, but it's not like his administration has stated anything beyond "israel has a right to defend itself" so even in the proper channels thre hasn't been much. (obviously the real statement is their new ~1bn weapons sales to israel this week).