I've had some pretty weird reactions when I tell people I don't use shampoo.. Just check out the comments in some of my curly girl videos... smh. I think it's really a gut reaction people have, and they don't listen to the explanation behind it; they just make snap judgments.
But on the other hand I've had fairly positive reactions to it as well. I agree that saying no sulfates, no silicones is the way to go. Some of my friends and my mom have even asked me to type their products or recommend things without "bad ingredients." I've also discovered from other curlies that some of them avoid shampoo just like I do, without even knowing about curly girl.
The worst is when a girlfriend asks to borrow shampoo though lol. I just have to be like, sorry don't got none. Or hand them my no-lather cleansers, which isn't what they think of when they say "shampoo."