If a parent doesn't want their child involved, it's not a required class or an elective, and it isn't held during the school day. If the parent doesn't want their child in the club, they can tell their child they don't have permission to go. It's the parent's job to know if their kids are making choices in line with their morals. It's also a parent's job to protect their child and make them feel safe. A LGBTQ child or their allies that fear violent repercussions or mental abuse because they go to a club, will not tell their parents and sneak. A child that can go to a safe environment won't need to.  
 I would like to see statistics and references to psychological studies to back up the data points in this.