I think that the baseline more obligation is not to be exclusive, i.e. whether you are working for free or not, you have an obligation not to design tools that

I think that the baseline more obligation is not to be exclusive, i.e. whether you are working for free or not, you have an obligation not to design tools that actively further harm to a group, demean or discriminate against a protected group, etc. The duty to be actively inclusive scales with commercial reasonability. For example, it would be reasonable to expect a small business to read aloud a menu to someone with a visual disability, at minimal cost. By contrast, it would be reasonable to expect a transnational company like Walmart to spend significant sums making stores wheelchair accessible. Someone who does something for free, or for incidental income, should only have to do very low time/cost accommodations.