Paladin here.
All things equal, a Guardian should be the MT over a similiarly situated Fighter class. I'm not sure that anyone ever "promised" that all tank classes would be EXACTLY equal. Obviously, a Guardian whose main focus is on mitigation and defense would tank better as far as straight damage absorbtion.
My paladin has heals/wards etc to compensate for his inability to absorb as much damage. Bruiser/monk is harder to hit. End of the day Guardians are by design damage absorbers which by design works better on raid mobs.
My first point is that nobody promised exact equality.
My second point is that certain people being elitest on raids shouldn't influence you. Raid with your friends, guild, or a pickup group. If they're being snobs and won't let you along then to heck with em - find a group that will have you.