The personal responsibility riff gets really problematic when you are faced with things like alcoholism or venereal diseases. People certainly have a choice to keep alcohol consumption down practice safe sex &c. But it's a reality that some people catch STDs or drink too much even though they should not, and these things have a way of affecting more than the afflicted individual.

And food deserts are a very real thing. If you live in one of those you haven't even much of a choice regarding obesity.