I would second the "filtering" really rubs me the wrong way. You just need to setup the events and friendships will continue outside of them, that's how if works. You can't know who will hit it off. The key is just creating opportunities. Half the people don't really know if they will be into something or not anyway.
Absolutely - it read to me like a grown up fraternity. Rush our social event and we’ll call you if you’re cool enough (or similar enough to us) to join the club and attend our invite-only poker night.
Maybe I just have a weird outcast complex, but I stay away from clubs that make you get “sponsorship” by shmoozing with existing members first (country clubs, yacht clubs). That really triggers some repulsion in me for some reason.
Instead, I’ve found a few friends from shared experiences and hobbies like my local cycling club, book club, and every now and again, car meets. (Even, weirdly enough, parents of people I grew up with and connected with later on in life.)
Even when I play golf, I do it at a public club rather than a private one.