I think they did have some principles, else they wouldn't have chosen to break rank to begin with. They just chose their tribe before their principles when it became obvious that the Left wasn't going to change for them.

There was a reason why they championed the "not real Liberals" line so much. Because they hadn't realized that "Liberals" were dead and devoured by the Left and had long since moved on from what they thought it stood for.

So they stood at a crossroads of joining the Woke or having to admit to having been wrong previously and join the Right they spent their whole life demonizing. And Pride won out as always.