Well, there's his sense of smug self-satisfaction, patting himself on the back as if simply making characters gay is in any way significant or praiseworthy. It's writer's slacktivism, an exercise in self-righteous ego stroking. (See: Modern Bioware)
Plus, it's just general bad writing. There's no depth. It's shallow to slap "A GAY" on a character as if gives them any meaning or depth. Not only that, you're just defining the character by their sexuality, as if that's all that there is to them. People are more complex than that. Good gay characters aren't good because they're gay, they're good because they're good characters.
I'm all for gay (or any type, really) characters, but you should make a character first and foremost, not a "progressive" cardboard cutout. There's really no excuse for doing otherwise; if you do a good job, people will accept it. After all, Marvel could make people believe in and celebrate a talking cyborg-raccoon and a walking tree; the sexuality/race/gender hurdle is modest by comparison.