A few smart people I know have responded to my TRB column about liberal disappointment the same way, which means I didn't make the point clearly enough. In the column, I noted that liberals have turned against literally every Democratic president of the post-war era. The response I've heard is that the disappointment was warranted in this case or that -- Jimmy Carter, Lyndon Johnson, Bill Clinton especially.
I mostly agree. My point is not that Jimmy Carter was a good president, or that liberals had no good reason to resent Lyndon Johnson. What I'm saying is that, if you're a liberal and you think every Democratic president is a disappointment, then you need to recalibrate your expectations.