Mo is short for Homo
It is common for females to dislike being referred to as a Fag Hag because typically Hags are old, ugly, and wrinkly. Fruit Fly is also disliked at times as it is homonymous with insects of the drosophila genus (i.e. drosophila melanogaster)
Rachel - I am not a hag! I am a moho. Get it right, tool!