Completely agree with your points and your frustration. It all gets back to the importance of putting thought into how a recipient will receive and interpret a message before hitting send. These are examples of senders not respecting the time of their recipients and just pushing their own agenda. And if you become one of “those” people, you generally end up in the Unread section of an Inbox over time.
Separately, as a long time fan of your writing, insights and a BIG fan of your move to Medium, I am going to make an unsolicited observation: this maybe should have been two separate posts. One about email etiquette around cc’ing and bcc’ing and one about assigning/identifying an owner for a task. While they are related issues, this one felt more like a stream of consciousness rant than a post. A little harder to follow than usual, which is a shame because both main points you are making are really important.