Yup, accessibility is literally about broadening the population of people who can use your software. It's often associated with affordances for the less-abled, but that's just a subset of accessibility. I don't get the hostility! Just a guess but maybe 1 in 50 or so developers I've worked with in the past didn't just "not care" about accessibility but were outright hostile to it, as in affirmatively "We should not spend time working on this!" Bizarre.