It's not a purity test. People are concerned about those who backed Clinton because Clinton was responsible for the worst Democratic defeat in a generation, that handed the GOP power on a scale not seen in almost a century. That screams of bad judgement. Like, if you backed such a bad candidate now, why should we trust you to pick good candidates in the future?
Crab, this is hindsight thinking and you know it.
You can think she's a bad candidate all you want, I don't even disagree with some areas of that thinking. But polling data and her performance in the primaries have plenty is reason to back her.