The swipe feature, while familiar to users, may not be the most efficient way for musicians to connect and form bands. A UX that allows creating a band and receive applications could prove more effective, then perhaps you can use the swipe to accept or reject them into your band.
Why not just list everyone... tables and filters for the end user
You give up on a lot of data you could otherwise have collected by doing that, data which could have helped the product in other ways.
Filters are useful to narrow a list but they're useless for actually recording a decision against each item in the set. They're just not a mechanic for assigning a (boolean) value. Swiping is, and that's what's happening here.