The issue isn't not choosing Bernie, it's knowingly picking the only candidate who could possibly lose. Because as GP said, they're in on the game. The goal wasn't to pick who they sincerely believed to be the best candidate for the country, including both fitness and likelihood of winning. So it's theatre, as they pretend to put the populace first, but clearly they don't.
Wait, so your theory is that the Dems:
1. Knew that Hilary Clinton would lose to Trump
2. Engineered the primary to select her as their nominee *because* of (1)?
No, I didn't imply that anywhere. Not sure how you read that. They knew she was a very poor pick in terms of "good for the whole populace" and "maximizing the chances of winning", yet chose her despite that, not because of it. The theater is the pretending that they have the best for the populace in mind, which directly contradicts this.
Or perhaps, the base and establishment of the Democratic Party (ie. moderate black people) rejected Bernie because they felt he was a bad choice.
This Bernie trutherism is really getting old, it's been disproven so many times.