They are pretty disorganized but there is organization. Not much leadership. But they do organize through Facebook groups, etc. They don’t just randomly and magically appear in places. Something doesn’t need to have a corporate structure to be organized. Chess clubs and book clubs are organized too. How exactly does one define an organization? If you can’t consider Antifa an organization, you also can’t call the KKK groups one.
The only argument you could make about him not being a fascist is that the US is still desperately clinging to democracy despite his best efforts. He’s not allowed to go full-on God-King, at least not yet. If he wasn’t so stupid the US would be in much worse shape, and when November rolls around I’m certain we’re going to see an even uglier side of Trump and the GOP.