I don't know where you get that "MAME is just a piracy tool"-idea from
trying to invent some funny backronym to make MAME more popular is probably not the way to go here
I mean the public image of MAME when mentioned in computer magazines (those generally tend to be (c)-trolls in fear of deterring their own paying advertisement sponsors). I do not try to make a fun of the name MAME at all, but in the opposite suggest to make it more serious/respectable because (unlike e.g. Linux) most don't consider it as a research and cultural heritage preservation project, but rather something embarrassing they don't want to get associated with. (Or have you ever e.g. heard a culture minister on TV positively speaking about MAME?) The situation is still much like when in 1980th acid house was more considered "a synthetic noise designed to further drug abuse" than a respected type of music, or when graffiti was mostly considered vandalism rather than art.