Gordon never questions the fact that the puppets are sentient and doesn't even seem that phased by their attempts at violence, instead treating it all with a weary gruffness. Because he's a human character on a muppet production. Even if that role is as a horror survivor instead of a friend or villain, the humans in muppet productions never treat it as strange to interact with puppets the way they do. Of course Gordon treats it as normal and is more concerned that they're (unintentionally) violent to him.
The five puppets involved in obtaining the Golden Ending all represent one of the five stages of grief: Pearl is blind and literally can't see how things have degraded in the studio (denial). The Pups have gone feral due to hunger and attack whoever they see (anger). Ray constantly tries to "fix" the plumbing without being able to ever address the underlying problem (bargaining, described as "the hope that the individual can avoid a cause of grief"). Goblette is depressed and apparently trying to feel better by eating food (depression)... and Ricky is fully aware of the situation and is trying to improve it for everyone (acceptance). To get the best ending, Gordon must help the puppets overcome their issues, but Ricky has already overcome his own; instead, he is the one trying to help Gordon, offering him a place in the Neighborhood as a way to deal with his own trauma. Sure enough, the bad ending is entirely caused by Gordon not even attempting to go through the stages of grief and burying it further under his promotion.
Besides war, there are so many horrible things the puppets could have seen on TV that made them realize how grim the real world outside the station is. Murder, torture, kidnapping, sexual assault, crimes against children, terrorism, mass shootings, natural disasters, vehicular accidents... and a lot of it would be not only horrifying but most likely completely incomprehensible to the puppets, who had never been allowed to watch TV until the show ended and their handlers left. For example, what would a sexual assault scene from a crime drama look like to a puppet who didn't even know what sex was?
: Pearl is blind and literally can't see how things have degraded in the studio (denial). The Pups have gone feral due to hunger and attack whoever they see (anger). Ray constantly tries to "fix" the plumbing without being able to ever address the underlying problem (bargaining, described as "the hope that the individual can avoid a cause of grief"). Goblette is depressed and apparently trying to feel better by eating food (depression)... and Ricky is fully aware of the situation and is trying to improve it for everyone (acceptance). To get the best ending, Gordon must help the puppets overcome their issues, but Ricky has already overcome his own; instead, he is the one trying to help Gordon, offering him a place in the Neighborhood as a way to deal with his own trauma. Sure enough, the bad ending is entirely caused by Gordon not even attempting to go through the stages of grief and burying it further under his promotion.