They said it applies specifically to the harem tag. so I assumed it meant that you can avoid side characters in the sense they don't have to be in the harem. Could have misinterpreted it though.
Viewing post in Tales of Magic School v0.1.3 - (Adult Visual Novel) comments
I had no idea how to parse that. Generally the further back I read in the thread the less I understood. My question was raised several times and for some reason a concise yes or no was never given, there's always an addendum or something that reads contradictory. I can't tell if it's just a language thing or the developer being elusive.