> This is conspiratorial thinking.

If you think the idea that politicians were colluding with each other (or cooperating for a more neutral word) is conspiratorial then you should just be disqualified from this conversation.

The difference is that their behavior is proper and makes sense, not an effort to steal attention from Bernie. I'll repeat again, the candidates were absolutely not burning through money, time, and political capital for a pretend presidential run to take attention away from Sanders. They were different flavors of moderate to appeal to the largely moderate base. Even if Sanders was entitled to more attention(he's wasn't), there is no reason to think Amy Klobachar or Cory Booker voters would go for Bernie over Biden when their policies are closer to Biden.