Hmm. I’m not sure I quite like the label “protestor/psych patient” that you have written in your description even though that may be accurate. Somehow this seems insensitive and pejorative. Then again, I am a psychiatrist and perhaps I am unduly sensitive to such perceived stigmatisation.
No judgment was implied in the description - I don't know what is motivating him, but some of his signage that you can't see was not fully rational. As was his behavior - he was playing the harmonica inside his box, and just playing seemingly random songs that did not have any special association with the "Me for Dictator" label. Perhaps his irrationality is a symptom of the times in which we are living and he's expressing it very creatively, or perhaps he's just irrational.
I'm seeing this now (after you changed the title), but my first impression was humor- whatever the guys mental state ... he's got a sense of humor! Or maybe as you suggest: an interesting and creative way of expressing an idea...certainly he's clever enough to use humor as a draw for attention...