I'm not naieve about how people do indeed rush to judgement, but I think it is important to highlight the flaws in this.
True but if I see a man wearing a gimp mask and PVC being led around on a leash by a woman wearing black leather/PVC and thigh length boots I will probably judge that they are into bondage (or some such derivative).
First impressions are our instinctive subconscious judgement based on our life experience. They should be tempered by rationality and reason but they should not be ignored.