I submit that the simplest "guideline" for Internet posting is: Would you be willing to say it to the person's face?
If not, then don't post it.
If so, then consider the probable consequences.
For myself, I've never been inclined to encourage "aggressive" posts (as I interpret such to be). Rather along the lines of "You can lead a horse to water..."
That being said, sometimes such aggressive posts have compelled me to make correspondingly aggressive reposts...and those are the ones that bother me the most.