The user admitted explicitly to engaging in behaviour that was obviously and blatantly in violation of rule #1. Disruptive behaviour is clearly described in the rules. I go out of my way to find reasons not to enforce rules whenever there's wiggle-room, but there's just no steelmanning when a user explicitly, directly, unambiguously and plainly states 'I am engaging in this for the express purpose of pissing somebody off' in public.
I rarely look at reactions on a post beyond an idle glance at the bar, so if these users have been engaging in this behaviour then they will be looked into.
Maybe I'll just lock reactions behind a minimum post threshold if there's multiple idiots doing this.