I guess it depends on interpretation of those comments
As long as it doesn't become personal, I guess it's fine... I mean some people call you a "hater" just because you say you happen to dislike a song, so it's truly what you say person to person.
Sure I agree,
anyone should be free and welcome to express any emotion about a song. However, if it is more of a rant, the person shouldn't be surprised to get passionate heat back and expect it without being butthurt. Not many of the usual ranters are any good at that. More often than not they get offended and responds with personal insults. So usually and basically it happens like this: A "hater" express something provocative (I don't know why, maybe to get sympathy or attention), he/she get a heated response (basically GTFO), the hater goes out of character and express a butthurt response OR
cowardly doesn't respond at all (which is truly awful). What do you do as a responder? In some rare cases the "hater" actually had a point, a cool approach and then some fun things can happen.
BTW It's not difficult to figure out what I meant with "campaign ranting".
It doesn't matter how much I understand the underlying purpose or origin, I become triggered anyway. I can't help it.