Most don't vote now, which is one of the primary reasons why Trump was elected.
Sure, they swamp social media with their anger, demonstrate, disrupt conservative speaking engagements, burn and vandalize private property and call for violence in the streets and revolution but have never really voted in huge numbers:
In a number of other key battleground states, such as Wisconsin and Pennsylvania, it looks like millennials didn't show up at the polls in the same levels they did for President Obama, and that was a problem for Democrats.
The millennial coalition Obama created just didn't translate to Clinton, despite the Beyonce and Katy Perry concerts.
In many of these states, Clinton still won the young vote, but her margin of victory was substantially smaller. In Florida, it was 16 percentage points less than President Obama's; Wisconsin, 20 percentage points smaller; and Pennsylvania, 19 percentage points less.
And I believe most younger voters once they have to pay taxes, raise a family, and start building their retirement and saving for their kids college, become more Conservative and less "progressive" or Liberal.