Why is sarcasm viewed as a bad thing?

I'm a very sarcastic person, with some dry humor thrown in. Really I'm always told you won't make any friends if you are sarcastic, but I manage to make them easily. Plus, being sarcastic doesn't automatically mean I'm a mean person. Well, considering I deliver my sarcasm with a good natured smile usually I guess people don't get mad. For example, my friend could beranting about how her BF hasn't called despite him saying he'd be working until late. My typical repsonse would be, "That , how dare he not ignore his responsibilities in order to text his profound love for you? Really, has romance died?"...*grin* Plus I rarely use it in anger, unless provoked. My sense of humor has made me semi popular so I'm kind of confused. I'm guessing this rule only applies to the people who have no verbal filter.