No, its not a bug, its a combination of class skills/guards/heals.
Its perfectly fair that higher lvl players have an advantage. Think of the opposite scenario, you just spent 1 month grinding out lvls and gear, and someone who played for 2 days is lvl 20 and is just as effective as you. Would that be "FAIR"?
Once you grind out the same lvls and gear, you'll obviously be on an even playing field.
If you want a fair game play chess or something, progression based mmos will never be fair.