Blame the pokemon in it, not the entire type. Only good psychics are legends or Alakazam, because all "modern" non-legend psychics are slow as crap and dark move distribution is amazingly common. Or they're part steel with stats on the level of a pseudo-legend.
Put psychic on a magmortar and slower fighting types will run in fright. Faster ones will just stone edge you and be done w/ it, but still. Psycho Cut is Gallade's saving grace, and Zen Headbutt gives several pokes decent coverage.