People into BDSM are definitely in the minority of all people, with less doms than subs, and less switches than either.
Neither of those two girls are switches, though. In fact, no one in that story is. Lisa is exclusively a submissive, and Allison is exclusively a dominant (although she found out about BDSM after experimenting as a sub while in a relationship with Alan). But who cares, lesbian bondage!
No but in all seriousness though, Nonesuch just hates fun. That's why he lives in Saudi England. We should start him a GoFundMe.