Actually, it's a known talking-point that showed up a couple of years ago, but it's back in vogue:
One creepy thing about this is how often so many people on blue media are suddenly saying almost exactly the same things. There's pretty obviously some kind of coordination going on. I guess they used to use the "Journolist" to coordinate. Not sure whether that's still a thing or what.
Their message varies a bit on this point, with their conclusion sometimes being:
Antifa is not an organization
and sometimes being:
Antifa isn't real/doesn't exist.
Sometimes they combine these into an argument:
Antifa isn't an organization
Therefore:
Antifa doesn't exist
I don't know whether there's some kind of technical (e.g. legal) definition of 'organization' that might make the weaker proposition/conclusion plausible. But I kind of doubt it. Obviously the more ambitious proposition/conclusion is just plain stupid.
This is, in general, a known rhetorical tactic of the left: pretending that the thing they're doing or supporting just doesn't exist at all--it's a figment of the right's imagination. They did the same thing with critical race theory. This is part of a well-known rhetorical trajectory the left gets on when busted for doing or supporting x: x isn't real/doesn't exist...x exists but it's a good thing...x is necessary/indispensable.
This is the kind of bizarre, quasi-philosophical nonsense we find so often on the left. There's a kind of tacit metaphysical claim here that shows up as an implicit premise in the argument above:
Antifa isn't an organization
[If a group isn't an organization then it doesn't exist]
Therefore:
Antifa doesn't exist.
Note, just ad hominem, that they had no inclination to reason in this way sevenish years ago when they were freaking out about the "alt-right"...
You'll note that some of them include a gesture at an argument to the effect that they "don't even know what Antifa is"...as if their ignorance somehow constituted an important premise in an argument. And, again: no one had much of a clue what the alt-right was supposed to be...but that, of course, was different...bigot...
This kind of inconsistent, ad hoc nonsense also shows up, just for example, with respect to transgenderism, where they argue, roughly:
Jenner thinks he's a woman
Therefore:
Jenner is a woman
The tacit premise, of course, is:
If S thinks that S is y, then S is y
Which is demonstrably false and, in fact, absurd. They accept this reasoning and this premise in this domain, despite that fact that neither they nor anyone else accepts it in any other domain...and despite the fact that they explicitly rejected the following reasoning:
Dolezal thinks she's black
Therefore:
Dolezal is black.
The academic left has succeeded in importing bad philosophical arguments (e.g. about "social constructionism") into political disagreements, invoking only the arguments that will advance their causes, and only in domains where this is convenient.
The "Antifa doesn't exist" nonsense is just that--nonsense. Perhaps if we were inclined to care, we might be able to make something of the claim that it's not an organization. If that were true, it would matter given that the administration has declared it a terrorist organization. Here stuff in the law will matter--stuff about which I'm entirely ignorant. I don't see how it could matter much, because, if there is such a distinction, it could, instead, be declared a terrorist movement or whatever. This would merely be a tricky legal maneuver in any case. It wouldn't matter much substantially.
The really important point here is: Antifa undoubtedly exists, and this talking-point blitz is just another case--one of many--in which the left is prepared to deny outright facts and accept utterly absurd reasoning for the sake of advancing their political projects.
Addendum: Purely imaginary!