ethically defensible to enforce a choice between not using a potentially useful app
Seriously? Your claiming that as an app developer I have an ethical responsibility to make it available to anyone who can find it useful? That's some heavy "with great power comes great responsibility" stuff.
I wonder how you square it with commercial app development. I guess charging money for an app is always unethical because some people may not be able to afford it.
I distribute my app only though f-droid so people with stock android will soon have issues installing it. I guess it's also unethical and I have to give my personal data to Google so I can put it in play store. But isn't it unethical for users to request that I share my data with Google? That's some serious ethical paradox here.
Does this apply only to software development or anything I do? I made a cake the other day. Would it be unethical for me not to give it someone who would like to eat it? Can I ask them to come to my home to get it or it's an unethical barrier and I should take it to them?