Massage and the Hobby

I've been a lurker in the hobby for a couple years. Im not mainstream and I dont post much however, during my time in the hobby I have become aquainted with several providers that are (RMT). Some providers appear to have legitamate massage therapy jobs, while they also hobby. My question is what is the ideology behind massage therapy(what is taught in school). Where some therapist practice legitamate massage in spas, and others tend to cross over into the hobby with theirs? Is it for the start up for their own business or because they enjoy the hobby or is it because it brings something else to the table. Its just something thats crossed my mind and I really never quite understood. Any help with understanding the difference between the massuse and a massage therapist would be greatly appreciated. I understand everybody has their own reasons for being in the hobby but massage seems to be something that comes along with the biz. Im just curious to hear some providers thoughts on that.