Sorry to slightly derail the point here, but "tone policing" seems to be all we get from most media, most government, and unfortunately most business leaders. It's not surprising that we see it all the time in online discussions,as it's become the new way of being "reasonable".
In Australia we are having a debate about immigration. The actual debate is over the treatment of refugees (or "Illegal Immigrants" as the government calls them) that arrive by boat. The refugees (sorry "Illegal Immigrants") who arrive by boat are treated very differently from those that arrive by plane. In the last few decades, the refugees who arrive by boat aren't even just "Illegal Immigrants" anymore, they're "Boat People". And we need to "Stop The Boats".
So, in less than 20 years, we've reduced the words "Boat" and "People" into snarling invective that the masses can spit at each other in self justifying jingoism.
I agree that the "substantive points" in any statement are the ones that need to be considered, but if the majority of a country can be persuaded to be in fear of "People" who arrive on "Boats", then we need to recognise that the delivery is just as important as the substance.
When we live in a society where "tone" itself can cause offense, then "tone policing" is probably, although unfortunately, justified.