It includes this important rule:
> In general, reviewers should favor approving a CL [changelist - equivalent to a patch] once it is in a state where it definitely improves the overall code health of the system being worked on, even if the CL isn’t perfect.
The goal should be that the reviewer understands the code and what it does and is satisfied with the other things.
In reality what often happens is a busy programmer looks at it, spots that there is a { in the wrong place, flags that and considers his/her job done and moves on.
If someone flags something in a way that you disagree/or don't understand the best approach is "Can you explain why you think your approach is better than mine and what the trade-offs are?" in which case you'll either get an answer that is satisfactory and accept their changes or not in which case you then have to escalate it again.
If you think of it as asynchronous pair programming rather than a chance for someone to nitpick everything you do then it's more obvious how to respond.
You can delay that point by been open and reasonable up to a point, if you can't then reach consensus you need to escalate it to a lead/PM.
It can get both messy and personal if you aren't careful because two programmers might often solve a problem equally well but differently and therefore there simply isn't a clear correct answer.
In those cases I'd tend to default to the solution of the person who wrote the code (simply because they'll have put more thought into each part than the person doing the review usually).
Team dynamics will largely play a part as well, you may have an incredibly good programmer who can't take criticism at all well (seen that) or whatever and then it becomes a management problem rather than a technical problem.
A lot of it is simply tone and empathy though, "I'm curious why you did A instead of B here?" against "Why the hell didn't you do B?" or "B is clearly superior!" (with no explanation of why or the trade-offs).
Asking clarifying questions is often a good way to drill down to the meat of the problem (and in a good code review environment imo one of the strongest benefits, it increases comprehension of the code and intent for all parties).
One of my lecturers used to say "there are no technical solutions to a people problem".
In practice, some teams do this very well and it an ongoing discussion of good practices that makes everyone better. Other teams nitpick over trivia, asking everyone else to code it like they would have. Some teams require an actual approval, others just toss all the code up for a while before merging it whether or not it got reviewed. Sometimes a lead reviews it all and say yea/nay, other times it is a teaching tool to expose people to new areas of the code before asking them to help out in that area.
In other words, no - there is no standard code of conduct across the industry. But there should be some common understanding of how your team, specifically, is doing reviews, and what expectations exist.
Careless, quick reviews are going to foster an environment where PR authors do not feel adequately supported where as pedantic, nit-picking reviews are going to exhaust.
As for the semantics, it's often about being idiomatic in the language and adhering to good design, i.e. if some requirement changes -- can this change with it?