Man, lots of anger here.
Not sure about the details of this club, but I have served on the board of ours for the past few years, and having wrestled with the very real concerns about club liability on sponsored dives, appropriate waiver language and the like. I would suggest that you be a bit more charitable and give people the benefit of the doubt before jumping to conclusions, drawing a line in the stand, or leaving the club in a huff.
Dive clubs for the most part are run by your fellow divers who do a lot of work as volunteers to try to facilitate fun dive activities, bring newer divers into the sport, arrange for trips, lectures, parties, etc... It's not like this is some big business that is trying to scam you. No one running the show is getting anything out of this - people are putting in a lot of work just so the members will have a good time.
One possibility is that they simply meant that you can't dive solo on a sponsored club dive, and whoever put the waiver together just got the language wrong. I'm in the process of reviewing our bylaws right now, and I can tell you that over the years there's a lot of cruft that accumulates. Not everything is written by a legal professional, believe it or not.
There are actually lots of pros and cons of specifying stuff like this for club dives. We actually try hard not to do things like vet divers' skills, arrange buddies, or determine who can go on what dive, because these things seem to increase your exposure. But another legal counsel may have advised the OP's club differently. Who knows.
You don't have to join a club at all to dive, but I can tell you that my dive club has made diving SO much more enjoyable for me, and that includes when I solo dive (there's lots of time to socialize during surface intervals!). So maybe ask for a clarification, but if that was their intent, and if you really like the people but not the agreement, then sign it and forget about it, as Dr. Lecter recommended.