Because they by running a business are responsible to ensure that they don't promote or willfully ignore harm brought about wholly or in part by their actions or negligence.

For actually moral folks the minimum the law requires is a starting point not the last word.

Eg moral folks ask is there anything I am doing that causes harm or anything I'm not doing that I reasonably ought to do to prevent it.

Smart people too as many governments take a dim view of dodging responsibly and will invent new laws to regulate you.