Ah, UK! Vs US English, I think. First off, libel laws in no way require blood alcohol testing to do anything, But I'll add to this later. And to report may be a US interpretation, but in the UK a reporter does not report. A journalist writes. In UK English, reporting a person means passing info on to an authority figure. Although I will admit, many younger folks seem to mix US English nowadays. So it is getting more confusing.

We also do not tend (as a society) to judge people for getting drunk. Unless they are in charge of something. So newspapers etc rarely have reason to comment on an individual who stumble out of a bar, vomit, etc. Most would only give a shit if he was supposed to be elsewhere. They report on how much it happens as a social issue often.

But you are correct, our libel laws get out of hand. But what must fail to realise, it is not the formation of the law that is the issue. You can indeed indicate a person seems drunk if their actions would be interpreted as drunk. You will notice the word "seems" holds a lot of weight in that sentence. As honestly it should. There are many other reasons a person may exit a pub to vomit and pass out. It would be bad journalism not to consider the possibility of food poisoning or health issues. Honestly, if you see someone pass out, you should be calling for an ambulance drunk or not.

The issue with our laws is more the cost. Because anyone can accuse someone of libel. As It is a civil matter, not criminal. This means you tend to be required to prove yourself innocent once an individual brings the case. This leaves the wealthy able to use the law to silence others. As few are able to afford a defence. The real issue is that libel is a civil offence rather than a crime. A serious complexity in our old system.

Put bluntly, assuming you are in the UK. I am technically able to start a civil case against you for any darn reason I want. Technically, I could accuse you of libel for insulting my nation with your original comment. But to do so, I'd be required to pay all my own costs. As would you until you won. At that time, you can ask the court to assign costs. And in a case like that they likely would (because you would prove I suffered no harm from the claim). But if I am wealthy, you are likely bankrupt and having to back down before we get that far.