That is factually false, and splitting the millennial vote on the immigration issue was critical to Trump winning in 2016.
https://www.kqed.org/lowdown/24448/how- ... l-election
The problem with the democratic party right now is that the people controlling it do so to the detriment of a large majority of the electorate. It's similar to what happened to the GOP in 2016. The problem that keeps this from coming to a head is that Bernie is a dumbass most of the time, whereas Trump was actually pretty clever during the 2016 campaign.
Also, a lot of these progressives have yet to realize they bought into the diversity scam which is a major source of the economic woes that motivate them most. Once they really see that, and when somebody comes along to capitalize upon it, you are going to see Dem Trump. Bernie is obviously not that guy, but the economic problems for many Americans is so high, and the globalist professional class has fucked enough Americans over and expressed so much contempt for the people they fuck over, that the backlash is going to be epic when it happens.
Dems may hate Bernie right now for seriously threatening to take the nomination, but he's kind of the one safety valve they have keeping Dem Trump at bay.
Nor is this that far out there of a possibility. If you recall back prior to 2016-sh, LOTS of conservatives and libertarian asshats were pro-immigration. Trump opened the floodgates and once people started talking about it and realizing how much they were getting fucked, the right turned against immigration in a flash. Same thing could happen on the left. I just think Bernie is too pussy to do it.
