That's a bit extreme maybe. You can still be knowledgeable and talk about something with authority, even if you aren't totally "hands-on". Someone like Chris Harris or Henry Catchpole wouldn't be any good at fixing a car, but I would put a certain amount of faith in their assessment of how a car drives, while there are people who understand the market for certain cars, history and heritage etc etc.
Alex doesn't bother me that much, as he is quite enthusiastic, and his content is more about having fun, doing silly things and going on adventures. It's not something I'd watch a lot of, but I can see why it appeals to some.
I think it's the ones who just buy fancy cars that I don't get. People like Supercar Blondie, or Shmee150 to an extent. While you can't knock them for putting in the work and being successful, I can't understand what people get out of watching someone buying expensive cars, but not really being knowledgeable enough to speak about them beyond what the press release has told them.