Being, by your definition, "good" as a marauder does not mean that they are good at the game. The class is the most OP in the game. Stealth, neverending fury, insane defenses, ccs, gap closers, healing, and loads of damage. Clicking buttons is so hard!
99% of Maradaures are playing it for the OP factor, so they can make themselves look good. How many PvP videos do you see advertised of Operative Leathality?