I don't think you can equate terms like "cracker" or "honky" to the disparaging remarks other ethnic groups are associated with. If you're "white", are you really offended if someone calls you a cracker? No, you laugh it off. It's not even remotely the same. Until you walk in someone else's shoes, it's not your call to tell someone what they should or shouldn't be offended by.
Regarding Parcell's, this is just another reminder that he comes out of the Bobby Knight School for Blowhards & Blockheads.