I can understand why considering this to be a difference makes sense when you are considering it from the perspective of personal morality. However I'm coming

I can understand why considering this to be a difference makes sense when you are considering it from the perspective of personal morality. However I'm coming to it more from the perspective of wanting to remove impediments to disabled people having equivalent access to able people. Now from that perspective it doesn't matter to the person with disabilities if the company is acting deliberately in a discriminatory fashion or they are doing it out of ignorance it still creates an impediment. The thing is that most sources of impediments to disabled people come from people creating procedures, designs or structures and not considering that not everyone has the same abilities. There are few people who have malice against people with disabilities so having deliberate acts of discrimination be the threshold would not be effective in solving the problem. I don't think we should even consider this from the perspective of morality or punishment. Corporations are amoral profit maximisers by their nature. When corporations don't create accessible sites what they save by not creating an accessible site is paid by the people with disabilities. The ability to sue over ADA violations is a way to capture this negative externality.