Even though the 19th century and first half of the 20th century was marked by racism, and the rise of scientific racism that tried to seperate humans into various categories (the legacy of which we are still trying to overcome today), and colonialism and other nasty stuff... I do not believe that steam or dieselpunk are trying to empower any specific race or culture. Though it might seem that most steam and dieselpunks write and create things with a European or North American flavor, that probably stems more from the fact that the most of those people were born in, or spent most of their lives at least, in those cultures and areas. I don't think any steampunk writer is going to create a novel or graphic novel about a mighty whitey trying to commit genocide against some stereotypical 'savage' African tribe, or a dieselpunk writer going about the yellow menace and portraying the Japanese as bucktoothed, nearsighted, and extremely treacherous. I think the genres are more about the general technological zeitgeist, and the look and feel of the era with some advanced tech (for the time, or based on what their ideas of the future were like), instead of the actual customs or values of the time.
Steampunk frequently has women wearing pants and doing things that would positively shock anyone back in the Victorian or Edwardian era (including most feminists or sufferagettes at the time), Dieselpunk would probably leave most racism and discrimination in the hands of the Nazis and other fascists of the time.
looking forward to debates:) I am absolutely sure that to "tolerance extremists" any story without one-legged african-american transsexual lesbian is totally racist. For normal people the mentioned subgenre will be judged according to its cultural significance. After all, we all know plenty of real-life stories of dieselpunk era with "yellow" beating the shit out of "white" and "blacks" gloriously serving in same ranks as "whites", at the same time cross-cultural influence was extremely high.
My immediate answer would be yes of course, just due to the way the question is phrased. It likely depends on what you mean by the word "empowered". However it does seem as if you're asking if a story which is written to glorify one specific race is racist. It seems a bit like you're defining racism there.
However if I am reading a story taking place in a specific historical era, I want the people to think and act the way people did in that specific historical era. I don't like when you have what is really just modern day people in old-fashioned clothing. That would include any negative attitudes or actions.
The merit of any work or genre or subgenre is in what it is trying to achieve. The same goes for race in fiction. Is the work/genre trying to elevate or denegrate? To unite or to divide? Is it trying to raise one race/culture/religion/ethnicity above the others, or is it trying to make that group's voice heard as part of the larger narrative?
A story that declares Green Eyed People the "Chosen, Superior Race" and all non-green-eyes are inferior, evil subhumans worthy only of servitude or extermination; yes, that work is racist, bigotted, and evil and has no place in any movement I would be a part of. However, a story that takes the perspective of a Green Eyed Person (assuming we lived in a world where Green Eyed people were historically repressed) and where Green Eyed People feel they have no say, then no, a work or genre where Green Eyed People feel safe to tell their story doesn't qualify as racist. If the hypothetical "Greeneyepunk" Genre reserves its stories to only Green Eyed Authors, then I'd call it Exclusionary as a group, but if the green Eye community openly welcomes Brown and Blue Eyed writers, then I wouldn't even call it that.
As a Brown Eyed writer, I even openly welcome the larger, more diverse audience it brings me.
In short, the question itself demands more context.