Is it relevant to include expertise with a code review question? Should this change the code review/answer?
It can be important, because it also affects the answer you want to give.
We frequently have questions from people learning the language - for those people, we shouldn't dive in giving information far in advance from where they are. Give them a nudge in the right direction and don't scare them.
Then there are people who know the language and just want confirmation that they're approaching the problem in the right way (usually wrt timed problems). Give them a full issues list/alternate algorithms/other discussions.
And lastly, there are those who know they're right, but just want someone to check that make sure no silly things have slipped through. Usually a simple answer, yes or consider this.
I was the other reviewer who rejected your edit, for essentially the reasons given in Glenn Roger's answer. It really helps to know the asker's level of expertise in order to pitch the answer at the right level.
For example, when answering a question from Winston Ewert there was clearly no need for me to explain all the details of the Python features I used in my answer, but in this answer you can see from the comments that I got the level of detail wrong. I wrongly guessed the asker would be familiar with Python generators, and so I didn't need to explain my use of them. More description of the asker's level of expertise would have been helpful to me.
Code Review is a bit different from other Stack Exchange sites in this respect. On other sites one always needs to keep an eye on the value of one's answer for third parties who might have the same question or the same problem (and so the character of the original asker is not so important). But it's less likely on Code Review that anyone will come along with the same question, so more of the answer needs to be tailored specifically for the original asker.