It's not hard to understand at all. Dominating the voting in the new-queue takes a lot of effort. When Bernie was in the race such efforts had a potential pay o

It's not hard to understand at all. Dominating the voting in the new-queue takes a lot of effort. When Bernie was in the race such efforts had a potential pay off. Now that Bernie is gone there's no longer any reward. The reward has now shifted to getting Clinton elected and/or keeping Trump from being elected. Incentives drive behavior.