It is true that both Israel and the US have a long — and unfortunate — history of working with the Palestinian Authority.
It was only in late April 2014 that Hamas officially joined the Palestinian Authority to form a coalition government.
This made continued funding illegal.
Not according to the law in the USA ...
And if one wants to say something about it apart from the law ... very simply it’s that Israel and the PA do have a certain degree of cooperation. Israel wants them for the administration of the civilians in their territories (Israel does not want their soldiers to be handling all those civilians) ... AND ... most recently the PA did cooperate with Israel im searching and aiding Israel in searching for the killers of those three Israeli teens.
For all practical purposes, Israel needs the Palestinian Authority for all those Palestinians in the territories, so Israel doesn’t have to deal with it every day and expose their soldiers to a lot of attacks.
The Palestinian Authority is not going away and Israel is going to continue to deal with them. It’s Hamas that they’re not going to deal with.