The color they're talking about is the color your typing shows up as. When a person enters the chat room, their name has a color, but the text is black. Some people change the black to another color and I have been in the chat room when someone asked that everyone use black because of their vision.
My personal opinion is that if a person chooses one color when the chat room is busy, it helps differentiate them from other people in the chat room and is helpful. That being said, if someone has a vision problem, I can understand them wanting to have all text be the same color.
As long as we have the ability to change colors for our own typing in the chat room, I'm all for it. I would not like to see one person take away this privilege for the rest of us and hope it doesn't come down to that. I love the chat room!!!!
That's my two cents!