Yes, I do. And while the US protects "I bet you X beats his wife", it does not protect "X beats his wife".

And "accurate descriptions of legal procedures" have nothing at all to do with the most serious allegation. The serious allegation is the beating, not the conviction.

I don't know exactly what the kid said, and the case is probably going to turn on really close parsing of both his words and the manner and context in which he presented them.

If he baldly said "this guy beat the shit out of his girlfriend", then he made a statement of fact. Not a statement of opinion. Not "from what he did to me, he seems like the type". Fact. Even if the cop had truly been convicted of, say, battery as part of domestic abuse, the kid would have had no way of knowing exactly what that battery consisted of. Saying the cop had "beaten the shit out" of his girlfriend would still have been speculation on the kid's part, regardless of any conviction, let alone a protective order.

There are no complicated legal technicalities there. The kid had no knowledge of the detailed facts of the domestic abuse case, and he knew he had no knowledge of the detailed facts. He wasn't only ignorant of the legal finding. He was ignorant of what actually happened.

It is negligent to present your speculations as facts. Negligence means not exercising the care expected of a reasonable person in a similar situation. Pulling something out of your ass and presenting it as true is not reasonable care. It was done in a video after the fact. He had time to reflect, so there's no possibility of mistake "in the heat of the moment". And there's no "I did it because I'm an idiot" escape from being found negligent, either. People are often negligent because they're idiots.

Now, if he had said "the cop was convicted of domestic abuse, which I assume must mean that he beat the shit out of his girlfriend", then he would have been presenting a reason for his conclusion. In that case, so long as didn't suggest that that wasn't his only reason, the truth of the conclusion would cease to matter. He wouldn't be considered to be presenting "the cop beat his girlfriend" as fact; he'd be presenting it as an inference to be drawn from the fact of the conviction. Then the audience would be expected to be able to make their own determination about whether that inference followed from the presented fact.

At that point, the question would be whether the kid was negligent in claiming that there was a conviction, because that would be the actual statement of fact he'd be offering. You might get away with claiming that was a mistake, but before you get there you have to show that he made it clear to the audience that the "conviction" was the reason he said that the cop had "beaten the shit out of" his girlfriend.

Then you'd have to argue that he couldn't be expected to know the difference between a restraining order and a conviction. Which is still not exactly open and shut, because a reasonable person might go find out before publishing a video like that. Not taking that reasonable care might make the statement about the conviction negligent and therefore defamatory. Because in fact reasonable people a lot younger than 19 tend to know the difference. A complete moron is not a reasonable person.

Or he could have done both: "The cop beat the shit out of his girlfriend, and of course that led to his being convicted". In which case there'd be two statements of "fact", each of which could be considered separately.