Why is Batman a Democrat?

Answer 1

In the comics, Bruce Wayne is fairly non-partisan. He supports specific local politicians that he feels are idealistic, uncorrupted, and good for Gotham. He also supports and runs various local charities. He does not publicly support one political party over another.

However, various real-world pundits sometimes use Batman story lines to support their own political perspective. This is more reflective of the pundit than of Batman.