Just putting the paid models on the stream, in and of itself, isn't inherently negative. In fact, one could argue that a viewer would then have to acknowledge there's a person in there, and not just an object to slobber over inbetween footage of adults playing video games.
It's having those models then respond to the chat directly, when everyone in the community knows it will be filled with nothing but adolescent attempts at shock "humor."
That's where "embarrassing" comes in. It shines a light on just how fucked up it is for tournament organizers to still be relying on old stereotypes regarding nerds and women, a light provided by the other aspect of the community that most members are trying to argue doesn't influence or represent the majority of the community - the "stream monsters."