It wasn't intolerant Liberal behaviour, it was a factual statement.

Facts have no political bias.

The Alt-right shouldn't be ignored, Racists and Supremacists need to be taken to task for their outlook., and people of all political persuasions need to be vigilant in this.

If an Alt-left develops they also have to be taken to task for that behaviour.

I don't think the Left ignores this issue, it's a non factual issue as you've stated, so what should we do, educate the alt-right?

That's the issue, since their viewpoint is non factual, they have a non factual way of looking at the world, how do we correct that?

One method is to make false news illegal, in Canada news has to be fact based, this isn't the case in the US. It's tough to police, here the primary policing of news organizations is through professional associations followed by legal enforcement.

Education, the avoidance of "false news" and an improved fact checking system seem to be required.