Of course, I'm going to stick my nose in.
Personally, I'd rather you take your kid to TGI Fridays than Hooters. But I'm not the parent, and it's not up to me what kind of message you're going to send. I just think you'd ought to be careful.
Taking a six year old boy to Hooters is not like taking your 18 year old to a strip club or your 21 year old to a bar. These are considered (as piggish as they might be in the views of some) to be rights of passage. They way I see it, you took your kid out to dinner to a place with overtly sexual themes that he was probably not able to pick up on at his age. Had he been a 12 year old, I'd probably have more of an objection.
If you want to take your kid to Hooters, that's fine with me, not that it's really any of my business. At the same time, you need to balance that out; it's your job as a parent. That means sitting down with him when he's a little older and he can understand these things better and telling him about how important it is to respect women and not be a chauvanist pig.
I think that at this stage in the game, this was just dinner out with Dad to him. I don't think you really did anything wrong, and I'm almost certain you didn't do any damage, but in the future I'd recommend really assessing things like this before doing them. Ask yourself some of the following questions:
Is this in some way going to negatively affect my child's development of morals or respect?
Am I sending a message that my spouse would not be comfortable with me sending?
Am I comfortable with the message that I might be inadvertently sending?
If I think that I may have sent a message that I did not want to send, did I take the time to discuss with my child what I wanted them to obtain from the experience and clear up any issues pertaining therto?
I know that might sound really like... well.. you should be paying me $175 an hour for it, but I think it's important to think about. Like, really important. I am personally disgusted by the attitudes toward women in our society: we say they are equal but they are so objectified by many. You'd be surprised how many otherwise well-educated and cultured men say things that are just... SO out of line in regard to women - I guess that's just the way they were raised. Which is why it's so important that you make sure you do a good job with your son. Dad is the role model for his son's sexual life - he sets the norm and is looked up to. I'd also really consider discussing this matter further with your wife since she did express some, though probably minimal discontent with your outing. Just to make sure everything is all squared away.
Oh yeah, and ignore the evil step-witch. She'll get you, my pretty, and your little son too. Never mind, that wasn't funny.