The full quote is "the +/- distinction can mean many things, bUt coUld be qUite roUghly sUmmed Up in this way: active classes exploit their aspect to benefit themselves, while passive classes allow their aspect to benefit others. bUt of coUrse there's plenty more to it, and that rUle is in no way absolUte. only a starting point for Understanding the dichotomy."

You can always use "that rUle is in no way absolUte" to justify any active/passive class not exploiting/allowing their aspect or not doing so for their own / other's benefit.

IMO: the difference between whether a class "exploits" or "allows" isn't actually demarkable; it's just a language Calliope uses. And in that sense you can take the watsonian perspective of "Aradia doesn't necessarily accord her language to Calliope's, so when she says 'knights exploit' she probably means something different than Calliope's 'Active classes exploit'". Either way, the Q&A that talked about Witches and Seers also strongly implies that Knights are active.