Pink hats, 
1. Suggested by P***y Riot, the ne'er do well group that desecrated an Orthodox Church in Moscow. Points on hats are supposed to represent a cat's ears, i.e. "p***y," and to relate to Trump's comment about grabbing women's p***ies.  

2. Or the points are horns. In western traditions, cuckolds have sometimes been described as "wearing the horns," an allusion to the mating habits of stags, who forfeit their mates when they are defeated by another male.  Horns are a symbol for a male whose wife has committed adultery.   

3. Symbol suggesting a color revolution, a specialty of George Soros, one of the main funders of this "spontaneous" event in DC.  Sexual degradation is frequently used in some fashion in such revolutions, because degrading ones moral sensibilities makes them easier to dominate and control.

edit: an automatic system censors the word "p***y," which is ironic inasmuch as Catholic women seemed to have no problem wearing the symbol for same.