Ethics is about humans in general, while Free Software primarily cares about the freedoms of software tinkerers. Most people won't magically feel more free or more ethical when their Wifi card stops working because something or someone wanted to exclude "non-free" drivers.
Free Software ideology (yes, it is one) also won't tell you how to make the lives of those people better who - for whatever good or bad reason - can't tinker themselves out of their problems. Which is mostly everyone. In that sense, teaching them about Free Software instead of about ethics is a similarly bad idea as wanting to teach people Christianity instead of ethics. Christian and Free Software culture give you some start when it comes to ethics, but can't replace ethical considerations themselves.