Biden is one of the more to the right Democrats in the party, and the right still hate him as about as much as they would if Bernie were president. He's damn near the definition of center in American politics. (worldwide he would be considered pretty far right)
The compromise just plain sucks, and that's why nobody likes the bill, and damn near no average joe of any persuasion gives much of a damn about it. I can't say I blame them. Any parts people really wanted, and even more, needed that would benefit the most people in the most impactful way were striped out a long time ago. I'm not just talking about people to the left, but even things poor Republicans might have liked were kicked to the curb. Hell you give Republicans a list of things without telling them a party affiliation of where they come from and they like a large number of progressive economic measure also.
When there is a compromise on a compromise of somebody's compromise that was already compromised where at each step things only gets stripped down from it to the point what's left is both inadequate and theater to maybe gain some half-assed PR it's past the point of being reasonable.
Worse, anything passed now will just be used against anything that even has a hope of passing for years to come no matter how much it's needed. Too many politicans will just point to it and say people got something, they already did blah blah blah, proclaim people should just be grateful for what they got, and wash their hands of it. It will be used as a tool against any further change.