Generally, when one types words and then posts them, they are speaking for themselves (unless you've gathered a consensus prior to posting).To me it is a piece of crap. I was not speaking for anybody else.
Therefore, there's no difference between you calling a song a piece of crap, and me calling them shitty. Yet your remark is somehow OK, because you're just speaking for yourself; while my comment earns a reprimand about personal taste. Sounds fair, right?