The other thing with climbing gyms, especially bouldering is that you only spend maybe 20% of the time climbing. With 80% time off, that's a lot of opportunities for socializing.

You don't get that with the high intensity training like Crossfit where you spend maybe 70% of the time working out and 30% of the time dying.

And socialisation happens naturally. You're waiting and lots of other people are doing the same. You are working on problems and can exchange tips or complements or cheer people on. It's inherently social.

The gym is not inherently social unless you are actively spotting / alternating uses of a single machine. You either join that group of gym rats (who in my experience spend 80% of their time talking) or you put your headphones on and crack on solo.