There are times when I would judge a person by how they look, yes. For example, if I were to walk into a restaurant and the waiter came up to me looking filthy, I'd think "hmmm, do I really want to eat here?" for example. But I doubt that a man with a dog collar and an outfit made of brightly...
Who cares what he looks like either. What's it to you? That's the whole point. If you judge someone by what they look like then you need to get over it.
With regard to the mess, I work in an office next to Preston Psrk and they generally clear it up bloody quickly.