Going to echo what others have said here because it's important: Your villain and your other bad guys can be anything without reasonable backlash, so long as the disagreeable things they're doing is not related to what they are, such as their skin color, their orientation, their culture or nationality, etc.
However, I've seen arguments from those who feel because a certain group gets so little representation to begin with, you must know that characters who are represented by said group hit much harder when they're villains, or poorly-handled.
If you have 1000 characters, and 10% of them are bad apples, or villains, that means 100 are bad. But a whopping 900 can be looked up to and accepted in the conventional way. This would be the majority who seem to be represented 99% of the time.
But if you 10% bad apples in a pool of 100 characters, that means 10 of them are bad, and only 90 will generally be beloved and looked up to, and feel representative of some groups.
This is the same issue that is encountered during the "kill your LGBTQs" trope. If a story only has 2 LGBTQ characters, if 1 is bad, 50% of the LGBTQ characters are bad in the story. Mathematically, it just doesn't look good. 
I always felt it was a valid concern. It's difficult not to notice and sticks out like a sore thumb to me when I see it, but that's not to say I always have a problem with it. I don't think writers should have to be representative. It's up to consumers to decide if they want to bother consuming the story, and they can have whatever stipulations they want to explain why they didn't continue to consume, but there should be no demand of a writer on an individual level to adhere to demands for representation.
Even if it's done right right though, you can still get what I'd say is unreasonable backlash. As an example, the writer who made Crazy Rich Asians was writing about his actual experience. Despite not indicating that "only asians are like this when they're rich", it still got backlash because several asians were shown in a bad light, even though no one said it was asian-specific (far as I know. I can see why some people would see it that way though since it's called Crazy Rich Asians and not Crazy Rich People).
