your example, it's irrelevant -- just because someone else crosses the line and does or does not get called out on it doesn't justify or vindicate YOUR actions.
I ask others to look carefully at who initiates these trades.
Personally, I don't have a problem with being on the receiving end, provided response in kind is acceptable.
I do object to be held to different standards than those who initiate such exchanges.
When I see the same standards being applied to those few with whom I am curt, as are being applied to me, I will take those standards to heart.