When you say ' someone dresses' ,it refers to the act of dressing and clothing themselves. "Both women dressed the same." The emphasize her is on the act of putting their clothes on. 'someone is dressed' means someone is wearing something, the emphasize is on the state of having the clothes on. "Both women are dressed the same." Both are wearing the same clothes. Examples: "They decided to dress the same and even wear the same make up for the party." "They put in an appearance in the party and were both dressed the same."

are dressed the same = wearing the same clothes It has NOTHING to do with who dressed them.