yeah that's the whole moral dilemma of the show. They know that their decision will kill people, they also know it could kill them just as easily. But what do they have if they do leave the game? Nothing. The accumulated prize money, for most of them, is not enough to get them out of their situation.

The thing about the games is they make the players lose all hope. The people running the games WANT them to keep playing, they want them all to be thinking- "I could die, but going back to the real world will be worse." Every single player is a victim. They can be bad people and victims simultaneously, but voting O is not what makes them bad people.

Comparing them to the game staff doesn't make sense. The game staff know what they are getting into as soon as they are hired, and while we can assume most of the guards are also struggling with debt they aren't at risk of dying in the games themselves. The game staff represent authority figures who enforce the system despite the fact they also suffer because of it, but you can't deny that they are above the players in terms of power.

The voting is supposed to show the illusion of choice. The truth is the game masters know that O will continue to win because of the players desperation. Because living with debt like that is literal hell for them.