I think "vulgarity" probably depends, at least in part, on the venue. Something that is acceptable to say on Facebook might not be appropriate to say in church, or that dirty joke one heard at work might not be approriate to repeat at home in front of children. It's all relative.

The link you shared, above, does not seem to be a conversation that should be out-of-place on Facebook unless children are present in your Feed. I agree that the person might have over-reacted, but it brings a good point of conversation here to the blockchain!