A lot of the young adults now are the people who were raised on play dates, Baby Einstein, helicopter parenting, and all the positive affirmation that the world can provide. They've been screwed by a bad economy and now they just learned that changing the world to one's liking is not a gimme. The defeat of idealism is a bitter pill but it will get better snowflakes. It will get better.
And we would have protests from Trump supporters had the result gone the other way. This is not unexpected considering the current divide in this country. As long as they're peaceful let the folks vent.
I don't remember any city protest marches when McCain or Mitts lost to Obama. Did they happen and I just don't remember?