Totally unsubstantiated claim. Not backed up by any data at all. True trolling depends on the sites you are on. Visit the Washington Post, Politico, MSN, NBCNews, or Time magazine, and all the forums and comments pages there are run by the Left, and anyone having a conservative opinion, no matter how polite or well-founded, is labeled a troll.
There are hundreds of places I see Left wing fanatics, who generally use the F-Bomb and other disgusting language MUCH more so than conservatives, as well as their quick use of hatred, vitriol, nonsense and group-think constantly and continuously. Try Reddit.com's /politics, for example.
The guy shouldn't write a story like this WITHOUT a really big mirror to look back at himself and his political cohorts before making such false and misleading claims.
This is the second time in as many day that I've seen the term "alt-right" used. I sense a meme coming on!