alt Hacker NewsOne of the issues with social media is it's difficult to quantify the harm caused, and that holds true for any form of mental or emotional harm. One form that definitely can be quantified are the social media moderators who have to sit all day reviewing explicit and illegal content.
I also think you need to review what you consider the barrier to entry for harm. If you imply that there needs to be chemical or physical evidence - congrats you just threw out most harassment cases.
Yes raising the barriers to what we consider harm is a good thing. Also, nobody is talking about harassment, that's already illegal.
In modern developed economies we don't have a problem with the barriers to harm being too low. We've got the opposite problem, where we've become deathly afraid of trivial imagined harm, resulting in us basically never doing anything and regulating new things out of existence (just look at the housing issue in cities in pretty much every developed country for example).