I think that a lot of the confusion comes from the semantics. While it's possible to use a compressor as an 'effect' (and it can be very beneficial in that role, or not...), that's not the same as using a compressor as 'treatment', where (if correctly applied...) it is always beneficial. If they were different units (FX compressor as a stomp-box, treatment compressors as rack units...), they'd be a bit more clarity. Until then, there'll be lots of folks arguing for one use, but ignoring the other. FX..? Debatable; the jury's out, discussing personal tastes and musical styles. Treatment..? Done and dusted decades ago, nothing to see here.