Can't say a word against it - you're still here, and not in hospital or morgue, after all. It would've definitely been worth a call to the PD, though, and I do hope you got a license number. If he
was a nutter, what happens to the next guy he decides was cussin' at him?
From experience, one of the toughest things we had to try to teach a rookie copper is the difference between backing off and backing down. The difference is, backing off is recognizing the odds, what it'll cost you versus what the payoff would be, and making a tactically sound decision to break contact - so that you can come back when the odds are in your favor. As far as the old guys and standing your ground if you're right, there are two points to consider. First, are the cops and the magistrate going to see it that way? Second, about being in the right and standing your ground, consider this little ditty:
a Tombstone wrote:
Here lies the body of John Paul Gray,
Who died maintaining his right of way,
Oh, he was right, dead right, as he sped along,
But he's just as dead as if he was wrong...
Bottom line, don't beat yourself up about it. If you're not satisfied with your performance, well, at least you're still around to prepare yourself to do better next time. You might not have been if you'd brought a pair of fists to a knife-fight.