“Democrats may well purge these guys, stay tuned.”
I am guessing that everything Democrats do is focus-grouped and poll tested six ways before they attempt it. I suspect that the focus groups and polling are telling them that America is not ready to go as far left as the party’s Left is pushing. Politicians who are in the game for the long haul are trying to steer as close to the middle ground as they dare. Either that, or individual Democrats are finding themselves in red or middle-of-the-road electorates and they are doing what is good for them in the long run.
I think that conservative politicians follow their own moral code and liberals do what they think will be popular.
What about Joe Manchin who voted for Brett Kavanaugh’s nomination.