Earlier quoted context omitted.
It may be legitimate when the regulated action causes direct physical harm to someone else. For example: I think it's reasonable to regulate particulate emissions. It's not legitimate to regulate manufacture or commercialization of products when that manufacture or commercialization poses no direct threat to the physical well-being of other individuals.
Why draw the line at physical well-being? Why should it be fine to waste someone's time, cost them money, even destroy them emotionally, so long as you don't directly physically harm them? Your scope is absurdly narrow.
Regulating emotions is arbitrary. Maybe it makes me sad that you post comments on HN. Should your comments be regulated?.
Physical harm is where you draw the line, because it's the only line that makes sense.