Yes, basically you do club rides at your own risk.

What you need to understand are that clubs are just groups of friends, volunteers, organizing these events for their local cycling community. They are human beings, they may make mistakes, but no one would volunteer if they could be sued when that happens.

This doesn't mean that if a vehicle hits you on the group ride, you can't sue the driver, it just means the bike club, organizers, etc. will not be liable.