I'd go further and suggest it's becoming increasingly difficult for anyone who's a deist.
The Democratic Party is becoming, as the article says, more and more closely identified with scientism, humanism, and atheism. Those are the only "isms" which overlap easily with dialectic materialism, the native "ism" of Marxism.
Or perhaps I've overlooked something. Comments?
No one with a brain can be a CHRISTIAN and a Democrat at the same time."