Extremism doesn't mean "fringe views." If it did, then believing that Elvis is alive, or that Hanson is the greatest and most influential rock band of all time, would be extremist viewpoints.
Extremism refers to support for extreme measures. Things like terrorism. Or solving the border crisis by gunning down anyone who comes across. Or solving the race issue by deporting minorities to their ancestral homelands, etc.
Advocating taking up arms (terrorism), murder at anytime, advocating deporting over half the country are all stupid extreme rhetoric. I'm not sure if they are promulgated as honeypot operations or just general retarded lashing out in anger. Maybe it's good rhetoric, widening the Overton window, to swing the available options closer to something that needs to happen ie viewing our government as not looking out for all of our best interests, closing down the border to all illegal immigration, restoring a sense of cultural and national pride, true patriotism.
It's certainly better than love is love, we're all the same, borders are only in your mind, gender is a mental construct and other inane, stupid mind killing platitudes.