To add my two-cents as a random player, I don't mind the bridge hobos, but I do agree that they lack in-game context and don't make sense.
They loiter at that location because it is a good spot to idle - central location, fun eavesdropping opportunities, close to the action without being in the way. It is safe without being too boring or out of the way.
The dorms are a horrible spot for idle socializing. Ugly, messy, boring.
The bar is better, but different. More active in some ways, but farther away from anything important. Also a little more dangerous - fighting is more common and explosions are not unheard of.
The holodeck, arcade, and pool area are not too bad, but hardly anyone goes there, except space tourists.
Chapel and Library might work. They are usually staffed and the staff are usually interested in RP. But they are both pretty far out of the way. Most visitors are just passing through on their way to do something in the Maintenence tunnels.
Departures is another potential hang-out spot, but to gather people there, someone typical needs to take the initiative and start building. It is a fun pop-up location for creative players. It would be nice if there were a few other spots like this, actually. It would give citizens more productive outlets, so they have less reason to idle and more opportunity to build cool stories.
In contrast, Arrivals is really out of the way and largely ignored. There is just nothing to draw tourists to the left side of the station. No important departments are located over there and almost no one has a reason to go back there after they arrive on the station for the first time.
The community garden area is pretty fun and useful for learning the basics of plant care, but not a good spot to relax and idle. If there was an actual green space near the garden with grass and flowers/trees, that would be a nice place to socialize and idle in a faux natural setting.
....
Anyways, regarding how to deal with the immediate problem, replacing the Bridge's glass windows with reinforced walls would be the simplest option. Also the least fun.
It would "solve" the issue for the bridge staff by taking away all interaction, but it doesn't allow any freedom to engage with the station or talk to the crew through the glass when you want. It is too harsh, imo.
Another simple change that might do the trick would be to change the shutters to be in the *closed* position on round start. The command staff can choose to raise them, if they wish to see and interact, but by default, the bridge would be closed to viewing. I would also make sure that all heads of staff can open/shut these shutters, so if they are talking about something sensitive when Cap is not on the bridge, they can shutter it.
And another idea - the shutters could be tied to alert level. They will automatically shut when station goes on red alert. This works both to protect the bridge, remind people that things are getting serious, and helps the command team focus on more important matters than bridge hobo antics. Since it is an automated action, related to station security, the hobos should not have any reason to riot over being left out and the bridge crew can't forget to close the shutter in a crisis. It works for both IC and OOC concerns.
Another option would involve redesigning the station to encourage people to idle elsewhere OR make the area in front of the bridge into an acceptable location for idle socializing.
For example, if it was possible to swap the community garden/tool storage rooms with the library/chapel, that might encourage people to hang out on the left side of the station more often. The dorms would be right across from two good socializing areas. Or move tool storage and add a "park" next to the garden.
Alternatively, the area in front to the bridge could be redesigned into a lounge with couches and the hallway could be routed up and over that zone. Idlers would have tables, chairs or couches to sit on. And a nice view into the bridge wgile they hung out and watched the world run by. They would make sense and not be in the way.
There are many options to solve this issue. Personally, I would prefer a creative solution that adds to the station, instead of just taking away something that many people enjoy doing.
EDIT - Looking at a map, I just realized that I was thinking of the clothing storage/locker room when people were saying dorms. Never realized the area around the pool was called dormitories. I thought of it more as a common room or public space, while dorms make me think of beds. Sorry, I am an idiot. Dorms are not ugly! They look nice. If I would change anything, it would be to rearrange the chapel/library to be part of the dorms or directly accessible from the dorms.
Perhaps a real hallway that runs from under the holodeck and down between botany and library so that the dormitories are no longer a dead-end and you can travel more than one way to reach your destination (without venturing into Maintenence tunnels.