If the squad gives the establishment the tiniest quote that's negative towards Biden and then Biden loses, the establishment will lay the entire blame for Trump on the left, the media will back them up, and the American electorate will swallow it. This is a time for progressives to let the establishment sink or swim on their own, not to provide an easy scapegoat.
The left has got to learn to let it's politicians be politicians. What works for an activist doesn't work for someone in public office.