High school (men's) gym locker rooms tend to be open areas with lockers lining the walls, sometimes rows of lockers like library stacks, and benches in-between the lockers, and an open shower. Private/public gym locker-rooms tend to be the same, sometimes with private stalls.

I've never seen a gym locker room with what you'd consider any privacy at all. Several boat-houses I've been to, that service crew teams, the bathroom/locker rooms haven't had separate stalls for the toilets. That shocked me the first time I saw it. I mean literally, toilets all next to each other far as the eye can see. Different norms and all but for a Western country, that should be considered savage.

The events in the article are at a YMCA, which is a charitable organization called the Young Men's Christian Association. It's a social charity that maintains buildings and facilities for public use. This is often a pool and gym, and sometimes sleeping arrangements. The quality and utility of these places varies wildly depending on where they are. They can be in an affluent suburb, and mostly provide pool access to children, or they can be filthy degenerated fuck-pits in a City.