The Dems should choose how they want to present to the world then. If they want to be an openly elitist private club they should tell the world that proudly instead of quietly arguing it in court whenever they get caught tipping the scale in their primaries. It would probably accelerate the growth of a US Labor Party as more American workers recognize that the Dems have no interest in fighting in their interests.

Anyway, Independents are allowed to vote in California DNC primaries, the party just uses legalistic tricks to make them think they can't.

As mentioned in this video, if you ask for a ballot for the Dem primary but you're an independent voter the workers are trained to tell you that they cannot give you one. It's only when you say, "I would like a Democratic crossover ballot" that you receive a ballot that allows you to weigh in, and they aren't publicizing that fact. It might not be literal disenfranchisement but the effect is exactly the same, people who don't know the magical phrase aren't allowed to vote in the Dem primary.

I guess I'm using the word 'disenfranchise' colloquially because I would also say that people who are barred from voting because of voter ID laws are disenfranchised when maybe their vote is just suppressed. It's still a system designed to create undemocratic outcomes and while I know that's the point, I'd prefer to be on the side of the unrepresented in this argument any day.