Just because the word MMO means “massive multiplayer online” doesn’t mean it applies to all online games that have a number of players online.
From wikipedia:
A loby-based game that has usually about 64 (max) players online on the same server isn’t really an MMO.
It don’t know why I’m replying since this has been pretty clearly explained by JBaldwin in my opinion but it’s basically as simple as that ? 