Your comment is a signaling of your likes and group-identities to strangers in an overt way.
> At risk of being reductionist, it is kind of hard to understand why anyone would feel compelled to signal their likes and group-identities to strangers in such an overt way. But I'm probably revealing more about my own personality by saying that than I am theirs.
I think the second sentence is more true than you might like to admit. People have been decorating things for as long as there have been modern humans. There is some evidence that even Neanderthals modified their environments for aesthetic reasons [1].
The desire to make things beautiful -- including our own bodies -- is as old as history itself, and even older. If you don't partake in this then I, for one, consider that a bit sad. You're missing out on a huge part of life.
[1] http://www.theguardian.com/science/2012/jun/14/neanderthals-...
To be fair (and as a sort of vote for the this-behavior-is-childish camp), I was much more into this sort of thing when I was a younger person.
At risk of being reductionist, it is kind of hard to understand why anyone would feel compelled to signal their likes and group-identities to strangers in such an overt way. But I'm probably revealing more about my own personality by saying that than I am theirs.