I think we can all agree that there is a difference between a personal attack, light teasing, and arguing a point. I think you/us are adult enough to see these differences and address accordingly. An option to deleting a post would be to first ask the author to edit or delete their own post if it is felt that it is out of line. This gives the author a chance to either realize he/she is out of line, or to explain where they are coming from. Remeber it is sometimes hard to here the tone of voice through a computer.
There is a difference between arguing a point and a personal attack. Having been rather frustrated by the later of the two, I found the "ignore user" function very useful. The line between arguing and personal attacks is not that fuzzy. Personal attacks shouldn't be tolerated.