At a recent design research conference I heard many statements beginning with "we designers..." or "the profession of design...". Almost all these statements are based on the idea that there are certain people that are designers and then others who are not. In many cases participants talked about the design profession (in most cases meaning "those of us who are educated in design schools"). It is as being a designer is a stamp and when you have the stamp then you are a designer.
The way design has developed over the last three decades has made it almost impossible to argue that design is a profession and/or a discipline, but still it seems to be a prevalent belief even among those who know more about design than most everyone else.
I like to make the comparison with other human approaches, for instance, science. Very few would state that being a scientist is a profession or even a discipline. Science is a way to approach the world with the purpose of creating knowledge. The scientific approach can be "used" in any profession and discipline. People engage in science. People engage in design. [Of course, there is the same issue in science, people who believe they are scientists and that science is a profession.]
Architecture has nothing to do with design unless people in architecture engage in design. Architecture can be exercised in a fashion that employs no designerly thinking or activities. Architecture can be performed as a scientific activity or as a process of art, or as a process of randomness and chance. Architecture is not in itself a design profession. Neither is graphic design, interaction design, or any other field. These words however do denote professions, that is, areas where professionals have the task of developing certain types of artifacts or services. They are in many cases also academic disciplines, but that does not make them into design disciplines.
Designing is an human approach for inquiry and action well suited for bringing change into the world. But it is not a profession or a discipline. A person is not a designer, but a person may use a designerly approach to fulfill their goals.