I recognized the airhorn sound (I have an AirZound).
I bike commuted for 28 years until recently and here are my thoughts:
Most drivers don't anticipate how their actions will affect other drivers, much less cyclists. It is up to you to protect yourself. My glasses mounted take-a-look mirror gives me a constant view of the road behind me as I look ahead. When I see an oncoming car, I assume the car behind me will pick that time to pass. I will then either take to the shoulder, or if that is not possible, extend my left arm in a "stay back" manner. The arm thing seems to work most of the time, but not always.
I no longer confront drivers. If they realize they put you in danger and feel bad about it they might slow down to apologize. This has happened only twice to me. But if they drive off, they either don't care or didn't realize what they did.
And if they put you in jeopardy on purpose, then they are not the kind of people you want to confront.
Regardless, your adrenaline is high having been put in peril, and if you confront a driver, especially one who is stopped off the street, the confrontation may raise their adrenaline.
Recognize the effect adrenaline has on you, and that it is already high from riding, and learn to not give in to it or let it cloud your judgement.
If your anger level rises pedal it out, you're on the perfect machine to do that. It is far healthier to stomp a bicycle pedal than it is to stomp a gas pedal.
For me, action cam video is to provide evidence in case of a collision, and to gauge my own reactions to crap that happens out there. Also to make nice video compilations of how great it is (or was) to ride to work.