Whatever the intent of the phrase "I see that the alt-right came out of 4chan" was—whether it was intended to mean "the alt-right, which is still a prevailing thing thing that exists today, came out of 4chan", or "the alt-right, which is a now-defunct term/ideology/movement, came out of 4chan"—it's incorrect either way.

And I'm well aware that "you" (plural) have all sorts of new blanket terms to tar disconnected groups of people and their thoughts with, so as to lump them together, so as to subdue any kind of thinking that exists outside of that prescribed by corporate media and the entrenched political class, by equating any dissident thought or position with that of the most vulgar individuals within the meta-group "you" (plural) created, by associating disparate individuals and small groups of people together using an emotionally-loaded label—regardless of whether or not its constituents agree with said labeling, which they don't have any say in, of course, because "you" (plural) have the in-group consensus of the general public on your side, which is informed top-down by the corporate media and entrenched political class.

But it's nevertheless interesting and amusing both that the "stickiest" one is—still to this day—one that was coined by an ultimately exceedingly minor and uninfluential figure, nearly a decade ago now, and that it's still wielded to this day by conformists with exceedingly simple-minded worldviews who see no problem boiling things down to "people who uncritically accept the social consensus" ("good people") and "people who are willing to entertain any sort of thought outside of the social consensus" ("bad people"—"alt-right", or whatever new terms "you" (plural) have concocted).

At least it's kind of nice to see that you tacitly admit to pursuing such a goal, in continuing to invent new terms for the same tired purpose.