Why would the left riot against a Libertarian?
The left is interesting in legislating a lot more than libertarians are.
I think because the left’s objective is to enslave the people, or at least the bottom 99%.
A libertarian, on the other hand, by definition has freedom and self-determination as major tenants.
Neither one is interested in morality. Just the end game.
I could be wrong, but that’s how I see the answer to your question.
Scratch a leftist and you'll find a fascist.
You might want to look into the matter further, it appears that your understanding might be a little off base. There's a reason that Libertarians most often end up voting for Republicans. They have more common ground there, than with the totalitarian left.
Why would the left riot against a Libertarian?
Liberal vs. Crypto-Liberal
Well the topic was working white men and why they are struggling. That was enough to anger the intolerant crowd.