It's a bit of the wild west for now, but you're right. Pretty much anyone can create a community, and I actually think that's a good thing. Have you ever been part of an online community that you loved, and it shifted to something you just didn't want to be part of anymore? When that happens, the decentralized nature of Lemmy and similar federated social media makes it possible for a new community to form and grow that is different, and for some, better.

Interestingly, when I search for motorcycles in the communities I only see two. This one, and another that has a single subscriber. Motorcycles are Fun doesn't show up for me. I think perhaps which communities you see depends on what server you signed up with, and what other servers that one links to. Right now I am signed into lemmy.world. I see from your photo that you were signed in to feddit.de. Perhaps OP was signed into a different server. This is a real problem for Lemmy IMHO. If I can't search and find ALL the Lemmy communities from my "home" server, and have to create accounts at other servers to see different content and communities, well, forget it. Caveat, I am also brand new and may not have a clue what I'm talking about, just observations from a noob at this point.