It's ironic that you'd claim to be acting in the name of common decency while invoking indecent violent behavior.
Let us invoke a hypothetical situation, however, to briefly consider why recording you in a public place should not be a problem. imagine that wetware is a real thing, and it is possible to transfer memories to a computer with full and vibrant video and audio... Lossy digital recording is possible today, so any imperfections in human memory are immaterial. In such a socieity, if you didn't want yourself to be recorded, would you get just as offended at anyone who was simply looking at you? If not, when in such a situation they could be using their memory as a recording medium, then why would you get offended today at someone who was using a visible device that might be used to record what is going on when that person probably wasn't even that interested in you in the first place until you got into their face and threatened them?
And of course, if you *do* try to beat the crap out of the so-called "glasshole", bear in mind that they would have a legitimate right to respond to such an attack in self-defense, and you could wind up getting yourself seriously injured instead.
If the device was actually recording at the time, the fact that you chose to instigate the confrontation would be irrefutable proof that this so-called glasshole was merely physically defending himself from your attack, and although what he was doing provoked the attack from you, it would be clear from the recording that he did not deliberately do it to antagonize you personally... you just happened to be someone who got offended enough by it to try and beat the guy up in response.
And failed. So.... you'd get beaten up *AND* still end up facing possible prison.
Think it's worth the risk? If you want privacy, go somewhere private.... if you go out of your way to do something to make yourself more interesting to somebody who isn't actually interested in you in the first place, then you are the one who is inviting the problems that may ensue, not the person recording their surroundings.