Isn't shmup an abbreviation for shoot-em-up? Because the other big genre during the period were Final Fight type games, formerly referred to as beat-em-ups?
I don't really dislike shmup, I am more disappointed by the lack of the term bemup.
I suppose the main difference would be that I've never heard anyone who wasn't a grandpa or British use the term "shoot-em-up" to describe a 2D scrolling shooter. Ever. "Beat-em-up" honestly became a good term to use after Street Fighter II, to distinguish one on one Vs games from ones where you and a friend team up to waste 367 dudes in 20 minutes.
As for "shewtee" or whatever. I don't care. It's just another infantile PCEFX term, I can handle it. Unlike "shmup" (honestly, I can't even type that word without swearing under my breath). "Shmup" is all over the Internet. Also, as unsuccessfully cute as fans of "shootie" (whatever) can be, none of them, and this is important, think that it's a real word, the standard term for something. They all know the f*cking things are called shooters.
Has anyone ever counted all the times EGM, Diehard, etc used the term "shmup" during the genre's glory days? (Or let's say from EGM#1 to the last issue of Gamefan)? I'm betting it's zero, or extremely close to it. Maybe a Brittish staffer or someone using it in quotes.