From what the little research that I did told me, nobody actually seems to be sure what steampunk is and what not. Sometimes dieselpunk was listed as a subgenre, sometimes as its own genre, just like Gaslight Romances.

It's about using Victoriana to make statements about our current time and place.

Yeah, I suspected as much, because I always thought that this was what science fiction and fantasy are both about. I like to use this argument to explain to non-fantasy-fans why I like the genre.