There's many different kinds of mental fortitude; just like there's many different kinds of fitness (bench press vs mile run etc). No one is saying Lockett isn't skilled nor are they saying the late score to come back wasn't impressive or mentally strong but the complaining to the ref and exasperated gestures when something doesn't go his way does show at best an immaturity and at worst a lack of mental toughness.
It kinda reminds me of Anthony Valencia; not saying that's Lockett's collegiate future . . . just saying I see similar behavior when things don't go his way