You wouldn't really envy him, cause he's being forced to do something he hates. Like if your classmates make you beat the shit out of black kids in your school or they will beat the shit out of you. [Good thing there aren't so many black kids in Russia lol
That's the think Koakuma, Balrogix pities the guy because he's forced to do something he doesn't like, but he also envies him because he would like to be the one smashing yu's.