Well, that's just it - I don't think he is, or is meant to be, his own person. That's why his story changes depending upon who he's speaking to.

I think the boats are meant to indicate that a mass of people can shamble towards goodness on average, mostly, and the acts of a few people can make a significant difference there. I mean, of course they considered it! People fear death. It doesn't prove Joker's ideology that they considered it.