Can vulgarity be poetry?

I think that poems that use vulgarity are better at catching modern day people's attention. I mean take for example how many people listen to rap music and sure to older people there is a big "shock factor" that comes from it, but young people flock to it. I guess really it's a matter of opinion, but I would much rather read something from someone who is willing to speak their mind even if people are going to be shocked by what they have written, than someone who tries to be politically correct all the time. So sure these poems do have some vulgarity to them, but isn't that the way modernism is, we are taught to speak our minds and be honest about how we feel, so shouldn't we study literature that is doing the same thing?