Spelling is based on pronunciation, not the other way around.
“Beyotch” (as I’ve seen it spelled more commonly) is not a mispronunciation, it is a totally different word with a subtly different meaning. Or do you suggest that you would get the same reaction by calling your girlfriend one or the other?
Also, it is nobody’s job to police the language and make it conform to your tastes.
OK, really, you’re just making shit up. Why do you think that’s equivalent in validity to the consensus in the field of linguistics?