I probably gave $100 dollars I couldn't really afford to Bernie. This seems like a minor technical change that won't change anything in the end. Russian trolls used anger at the DNC to get Trump elected so I don't know that I'm going to wash my hands of the whole party because they saw Hilary as more electable or whatever bullshit they might pull in the future. Republicans on a good day are arguably evil and we're living through the worst of what that party can do. It's not pretty
I also think the practical effect of the rule is small. The main point is that it is clearly a fuck you to Sanders, which I don't think is a good posture. They should be thinking about inclusivity more than almost anything.