I'm not saying they have to compromise on their highest priorities. I'm saying, they shouldn't expect to dictate the party's agenda if they refuse to join the party. It's fine if they want to fight for a very conservative faction of the Democratic party, but as I said above:

"As "Saint Joe Manchin" put it, if you want more Reaganite conservative policies, you're going to have to elect more Reaganite conservatives."

You can't refuse to join the party or even be such an infinitesimally small faction and expect to dictate terms.