I was seeing people assign more value than "boys will be boys" to the potentially underage drinking and that I found hilarious. The other stuff is potentially disturbing but I was not commenting on that for that comment.
The legal definition matters a lot. There is a way of manipulating conversation using such things -- if the guy is a judge sitting in a what is normally fairly serious and legally binding hearing with politicians (I don't know the full laws here but every legal and governmental tradition that makes up America's take on such things that I know more of would say take them seriously, court seriously).
Spin it another way. I am an engineer. Ask me what a strong material is and I will tell you. Ask me what a tough material is and I will tell you. They are not the same thing, not at all, despite what the general public might think. Amusingly that is a distinction that has to be made in court and a literal example from one of my text books covering court interactions (in this case a lawyer was repeatedly using the wrong word despite being corrected several times as it helped their case).
Secondly the legal concept of mens rea (guilty mind) is modified when various parties are "blackout drunk".
I dare say we have a slightly different interpretation of unanswerable questions, to say nothing of the whole point of the court there being to be the final word on questions that are asked. You ask someone something they will likely not (assuming they have not got serious skills most normal people do not, to say nothing of in the case of the law nobody knows how many there are) be able to answer on the spot. However you get to see them start to outline the problem and puzzle out at least where they would head in such things and from that you can tell a lot. It is not necessarily quite the same as the issue spotting exams that law schools favour but not far off.
First of all, boys will be boys is not a sound defense for any sort of behavior. It's an explanation used by many to cover behavior that is reprehensible such as bullying and hazing. These activities for years have been defended as "boys being boys" despite the emotional and sometimes physical turmoil they can cause.
Second, the matter at hand isn't if he had one beer underage and I've literally not seen anyone saying he drunk underage and just that as some kind of moral argument against him. There's a difference between underage drinking and repeatedly drinking to the point where you don't remember things i.e blackout. Most people have an issue with the multiple reports that Kavanaugh drunk to the point where he was belligerent or blacked out. I haven't really seen anyone upset simply at the fact he drunk underage.
Third of all, that's not an unanswerable question to my understanding but more of a critical thinking exercise. The reason neither side asked any of those questions is because they don't want a judge who's going to demonstrate critical thought. They want a judge who's going to make decisions straight down the party line. I think some of our misunderstanding is coming from the fact that the political and legal worlds may overlap but they are in no way, shape or form the same.
Politicians don't care if a judge can think critical. They care only about the decisions he will make on key issues. This is what the confirmation process is really about. The majority party puts up a candidate with views it supports and the other party attempts to undermine them unless there's enough moderation in the candidates views for their to be an agreement meant.
Part of that is the issue with Kavanaugh. The worry is that he will be a key vote for conservatives on many issues, where as the Judge he's replacing Justice Kennedy was often a vote that could go either way. This is why this process has become so critical.
I agree that, in a perfect world, the process would be about the fitness of the candidate and his personal views wouldn't matter. However, that's not how this process has worked for many many years if ever. In fact, many people of both parties are calling out Kavanaugh for saying what comes around goes around, Democratic conspiracy, and all of that in his opening statement for this very reason.
Also on that note, to gain my personal respect, which I know doesn't matter, all Kavanaugh would have had to do is behave how a judge on the highest court in the land should behave and be cool and calm under pressure. To say he didn't do that would be a massive understatement.