Are you able to further clarify if there is or is not standardization for what constitutes invective language, differentiating it from brazen noninvective language?
I would cite the example I gave to Triangle: "were you to say something like "gay people are f**king bastards who deserve to be sodomized at the stake," I would take that as invective. Invective is a degree of harshness above mere insult." Can I give you a precise brightline? No, but that is a perpetual problem in all rule-making. Ultimately, determining invective requires me to make a judgement call in each case.
As for marginalized groups, I am not so much referring to groups on this site, but to social groups which may be marginalized in society writ large.