It's entirely true. I'm known for having a short-temper and my preference to get up close and take obstacles head-on, and therefore passionately committed to my WoW warrior. And physically, I can take a lot of hits, and get very protective of my friends, so I also naturally tank with both a warrior AND a paladin.
And I know two guys who are probably the nicest, but kind-of wishy-washy guys...They play paladins, and just about paladins ONLY. >.> Go figure.
Since in real life, I can soak up a lot of damage, when I do roll pally, it's usually holy/prot, and can probably fall down a jagged cliff with a nice buff, heal my crippled body, and walk away. And I never like to play a class that wears anything less than mail.