They could at least give some reason for it, other than the obvious "well, swords and stuff are cool". The Dune universe had lasgun/shield interactions as a decent explanation for why melee combat still exists. Star Wars even handwaved it away with magic... err, I mean The Force. Star Trek sure had Kirk participating in a lot of random grappling combat for no real good reason, but at least they were still being armed with phasers for away missions instead of battle-axes.
Really though, I find it ridiculous, but it doesn't bother me all that much. I like fantasy stuff, and the fantasy tradition fits in with the DIKU-mud descendant gameplay most modern MMOs fall under a lot better than scifi does. Practically from the beginning, fantasy has been about acquiring magical items, and fighting against morally unambiguous bad guys, and starting as a lowly farmhand and ending up saving the world, all of which slot neatly into MMO tropes.
Scifi as a genre is more nuanced, frequently involves more politicking, and if you're trying to be somewhat realistic, is all about either projectile weapon combat, which fits more into a shooter game, or massive space battles which are more along the lines of a Wing Commander space sim or Master of Orion style 4x game than a WoW style game.
