It's their job to come up with things to be offended about and to try to convince everyone else to be offended too, and then to try to enforce this. Or, just skip straight to the enforcement part.
It's sort of like art. If you can interpret something in many different ways, then people with enough time on their hands can come up with negative interpretations about anything, and then promote this view.
And they share ideas within the ideological conforming groups. So people will sit and think up 'microaggressions' and then the ideas they come up with are used by other groups.
It's highly destructive and creates divisions and dysfunction, but that is a feature of the process.