Where did they come from? Why do people use them instead of the normal spellings?
I've just seen a video on insta that someone I follow shared. It says they are words used by T*s to exclude TW.
But the only people I've ever known to use the alternative spellings are people who believe TWAW 
It's getting to the point where even "trans-allies" are going to be saying 'transphobic' things!