For me? I suppose I got into it initially via social justice, and then as I started moving towards identifying as disabled and noticing more and more ways in which the world of the flesh was horribly inaccessible to me, I got more and more interested in making sure that people with different access needs than mine didn't get tripped up by 6" kerbs being left all over the shop at "home". So. Yes. Via analogy to my own experiences (I don't use assistive tech myself), largely, but also through Wanting To Make Sure Everyone Can Participate.