What he actually said was
“I got interested in the class element of Batman: He’s a rich man who beats up poor people. It’s quite a bizarre mission to go out at night dressed as a bat and punch the hell out of junkies. And then he goes home and lives in this mansion. There’s an aspirational quality to him—he’s an outlaw and he can buy anything. He has a new Batmobile every movie. He’s very plutonian in the sense that he’s wealthy and also in the sense that he’s sexually deviant.
Gayness is built into Batman. I’m not using gay in the pejorative sense, but Batman is very, very gay. There’s just no denying it. Obviously as a fictional character he’s intended to be heterosexual, but the basis of the whole concept is utterly gay. I think that’s why people like it. All these women fancy him and they all wear fetish clothes and jump around rooftops to get to him. He doesn’t care—he’s more interested in hanging out with the old guy and the kid.”
which is a bit more nuanced than "Batman is a homosexual!!!!"
The class aspects of his statement are more interesting to me.
So basically Grant Morrison doesn't like Batman. Another reason he is a bad Batman writer.