Acting out of anger and its results

When I was very little, probably from ages 3-7, I used to roll down the car windows and yell at people.
"Put that child in a safety belt!"
"Stop smoking!"
And various other things.
I remember on a road trip into West Texas I made signs about how evil hunting was and put them up against the window. Dad made me take them down because he was afraid someone would shoot at us.
Of course, while it's somewhat funny to imagine an even smaller Kate pronouncing edicts on passers-by, I can imagine that my efforts did very little good.
You see, anger breeds anger. When someone yells at someone else, the response is usually to yell back (unless you're like me, in which case depending on the argument I more likely than not try to run away).
Look at a football game (and no, I can't believe I'm using a sports metaphor, either): when the offensive team is coming on strong, the defensive team steps it up to combat it. They don't step aside and say "Oh my, you're right, here, go for the touchdown. You've proven your point brilliantly."
This is why in a heated debate, when emotions are running high, no one seems to get anywhere. I'm sure you've seen two people yelling at each other, regardless of topic, and you knew that neither one would yield.

I've had people tell me that using tact or approaching an argument from a roundabout manner in order to make the other person see for themselves that they are wrong is dishonest, that it feels like lying. Those same people tend to try to be combative and attack an argument head-on. I think that if you really want to convince someone that they are in the wrong, you have to go for the weakest part of their argument, which often is not the forefront of the person's platform.

I regularly read a certain blog and am considering discontinuing my readership. The blog focuses on outing people that treat animals badly. A lot of good has come from it, but at the same time I believe much hurt comes from it. Readers go to the featured person and, using foul language (never a good way to propose change, by the way) attack the person instead of kindly saying what is being done wrong or offering a small suggestion, or even better referring these people to the local authorities.
Then they link back to the blog entry, so the person being exposed eventually comes onto the comments page and tries to defend himself/herself against sometimes as many as a hundred different readers. The trap is set. The person tries to put up a good fight, but is eviscerated by the other posters. In defeat, the person retreats (usually threatening a lawsuit, to replies of "I dare you to try" from the blog author) and absolutely NO GOOD is done. Nothing changes. None of these people say "You know what, now that I've seen my pictures on your blog, I think I really do need to make an effort to fix this. Will you help me? May I have suggestions?"
Furthermore, the posters on the comments attack each other. They do this after misreading a comment, after noticing spelling errors, etc. In a place where a common bond should be evident, anger and disdain prevail.

I know that in this day and age tact and diplomacy have virtually gone out the window. We need not worry about how the other person feels or really affecting change in any way because the other person is behind our computer screen and thus faceless. It frightens me to imagine people speaking to each other face-to-face in the same way they do online. What frightens me more is that my generation seems to shirk off grammar and spelling, along with general disregard for all others besides oneself. At least, these are the people choosing to come to their keyboard.

I have often been told to leave a situation which angers me, calm down, and then discuss it rationally with the offender. Have other parents decided to take a "shoot first, ask later" mentality in teaching their children?