Bridge is just a file browser. Nothing more. It cannot open, edit or save any file of any kind. Bridge just hands the file(s) to the appropriate application, be it Photoshop, Adobe Camera Raw, Illustrator, InDesign, or even MS Word.
Therefore what you are seeing is expected, normal behavior.
You must be thinking of ACR (Adobe Camera Raw) hosted by Bridge. If that is the case, select your files in Bridge and control-click on them. From the drop-down contextual menu that opens, choose "Open with Camera Raw".