I have 4 black sex-link hens, all just about a year old now, and none of them are mean. I didn't make any particular effort to make them "tame" when they were young, either. I can even pet them a couple times when they're roosting (or waiting for a treat) before they sidle away. I've never had one of them try to attack... unless you count tasting my shoes.
I actually started with 12 (we processed 8 of them at about 20-24 weeks) and the rest of them all had the same attitude. They were all curious, a little bit cautious of people (without being afraid), and never mean. I think you just got a "bad egg", so to speak