In most states (IIRC Utah is the exception) one is allowed to drive an automobile with a blood alcohol level of .07999999
Being in that condition is the textbook definition of not being "fully in charge of him/herself".
But luckily there's a blood test with which a prosecutor can measure the level of impairment.
In a case like this there's no blood test available.
What this guy did was almost certainly bad form...maybe even foolish.But not criminal.
Well, all I can say is God Help You! if you take all of your *wisdom* from the Great God Science and people with Higher Ed Degrees
A lot of scientists are truly brilliant; but a lot also have supreme book-learning while possessing very little good sense.
As you admit, a blood test cannot determine emotional or mental derangement. But what used to be considered ‘normal’ people of ‘average’ intelligence could reliably sense when something was ‘not right’.
If it goes to trial, a jury of ‘normal people’ will decide if what happened was ‘criminal’ - not you nor I.
I just don’t have a problem with the arrest, or with having the case investigated. A man of diminished capacity died who WOULDN’T have died, if someone hadn’t played around with him just for laughs.