MF has been around since before I was in the military 60 years ago. Its use on the street is so common that it is now an acceptable part of the urban patois.
It now has several meanings, both derogatory and complimentary.
It depends on who is the MF and the exact usage of the word.
Those of you who are offended need to keep it to yourselves.
I used [redacted] because of the “frpottymouths” Karen on FR — this way the topic stays up. :^)