A lot of times there is just too much traffic in the rooms. Even if you create a private room without a password and say "priavte chat please" people don't read the name of the room they just look to see who is in the room and come in and start changing the conversation to themselves instead of concentrating on the person that needs support. So, I will password protect the room so I can control who comes in and out of the room and I can make sure we stay on topic and support the person that needs to share personal information.

If you see a chat that requires a password you can always PM someome in the room and see if you would be allowed to join. That is what most do to me, I read the PM and give them the password.