The squad/each squad is a group of highly qualified people of a quasi-law-enforcement nature who can be called in under a specific set of circumstances.
You know when someone with a superpower just wants to live a normal life but the evil-doers are destroying all good things in the world and somebody has got to take a stand? That's when you call them. They take a stand. The person with a superpower is allowed to keep their self-determination.
If they want to be a normal person living a normal life then The Superhero Prevention Squad is there to make sure they get that option. Normal law enforcement can't or won't handle the situation and it looks like the situation calls for a vigilante in a costume who can bend or break the laws of physics? No. Call The Superhero Prevention Squad.
Don't let life origin story you into a career you never wanted or asked for. The Superhero Prevention Squad exists to stop you from being origin storied into anything. Make your own decisions. Be the master of your fate. Leave fighting crime to the professionals.
The fact that you can teleport/phase through solid matter/take an RPG to the face without flinching/crawl on walls/shoot beams from your eyes/fly/turn into a giant monster/whatever doesn't mean the universe should be able to railroad you. You deserve the same chances and opportunities as anybody else.
That's why there's The Superhero Prevention Squad exists. Just because somebody has to take a stand doesn't mean you have to. They'e been trained for this, they've volunteered, they have great medical coverage (full dental!) and the best mental health care a quasi-law enforcement agency with hover jets can afford.
Sure, they might not have powers, but they have training, technology, experience, institutional support, and a choice in the matter.