“There’s every reason for people to believe X, but I’m not going to comment on it” is commenting on it. If your friend said “there’s every reason to believe GSF murdered a hobo for fun, but I’m not going to comment on it”, you’re not going to thank them for not commenting on it.
Biden has been WAAAAAY too deferential to Israel, and this is kind of a weak ass way to say it, but it was definitely said.