I’m referring to their DS9 incarnation, not the new show.

I kinda come down on the side of space KGB.

Most of the actions they did, was just standard spycraft that you would see in any war, and the dominion war was as brutal as you could get.

The worst action you could say that Sloan and section 31 attempted, was trying to genocide the founders via that genetic virus plot. Probably okay because the founders were all collectively involved (excepting Odo) in brutal space imperialism, subjecting the entire delta and alpha quadrants to subjugation and enslavement from their home planet, that was the target of the virus.