Lobby their colleagues in the Senate and the White House for the aforementioned boycott and sanctions, rally their constituency behind the cause,

What makes you think they aren’t doing that?

generally do a better jobof forcefully repudiating the criminal leader of a fascist apartheid regime currently committing genocide than saying lukewarm stuff like “it’s not a good time right now” and “too divisive”

They’re literally doing more than that. RTFA. Hell, read the one sentence quote from the article at the top.

So they’re doing what you want and it’s still not good enough.