I don't even know what this person is trying to accomplish, other than being rude and telling me to shut up.

Maybe get you into looking at what people are actually saying and taking some time to come up with replies that actually address that content in a meaningful way, instead of just responding with cached thoughts like "Republicans are crazy" or "shouting is rude". And to realize that coming up with thoughtful replies isn't just a question of figuring out the correct etiquette, but requires skill and insight which you might not always have.