Write Away

I think you hit it on the head when you said that you should write a variety of characters.

I remember of a few conversations, both online and in person, where one person would say that writing evil or otherwise immoral race/sex/identity/orientation minorities was discriminatory. I, as a bisexual person, can definitely get sick of the "depraved bisexual" trope. But that doesn't mean that all gay/Latino/female/etc characters need to be moral, or good, or puppies and rainbows. They just have to seem like real people. Go ahead and make an evil gay man. Just make that man 1) not evil because he's gay (i.e., the gayness isn't evil, but he just happens to be both gay and evil) and 2) make him more than gay and give him a background and a personality (maybe he's a bad singer, maybe he's evil because of parental issues, maybe he's allergic to dogs).

Those are the two problems I see with depicting minorities. The piece, particularly if the creator is not a member of that group, often reduces the character to only being a member of that group or the creator equates the character's role with the character's demographics. It's not wrong to have, again, an evil gay man. It's wrong to equate being evil and being gay, and it's wrong to make him nothing more than gay. It's not wrong to write a black gang member; it's wrong to say he's in a gang because he's black, and it's wrong to give him no identity beyond that.

There's also the stereotypical behavior issue. Some gay men lisp, but that's so overplayed that you should really just not do it because people will dismiss it outright unless you write it really well.

My personal opinion is that characters, no matter their demographics, should be full characters, not just roles in the story. Approach from both a Doylist and Watsonian perspective. Don't just think about why you as the writer want them there; why would they put themselves there? This not only makes more enjoyable characters, but helps to round out personalities and counteract reduction. If you want a true-to-life character, you need to treat them like actual human beings, not just filler for the plot. That's true for all characters, but it greatly helps produce less bigoted portrayals.