I've recently read some crits by people who should realize it applies to criticizing stories as well as writing them. A good way to get me to not take your crit seriously is to come across as mechanically applying rules that you picked up from some how-to-write book with no idea how to apply them -- and a noticeable penchant for following them over a cliff. And then you throw that rule book at my head. . . .
If you wish to avoid this issue, some ideas:
Do not quote the rules. Do not declare
- avoid adverbs
- you should omit all words that aren't necessary
- your sentences should be noun-verb-object
When applying them, you have to remember that the writer doesn't want to follow them over a cliff. Even in the grammatical arena -- whether a sentence is run-on is absolute (and you want to get it right) but whether it should not be -- well, run-ons can be useful for conveying certain confused, baffled, not entirely sane frames of mind. Other rules are even more tentative. (And be wary of assuming you guessed correctly what the author's intent was.)
Similar problems arise with historical information. Besides getting your info right (ranted about here), there is the little issue of whether the writer's fictional world has to abide by that. Recently read a book where the anointed monarch was the kingdom's scapegoat. Royals were kept prisoner and bred for the purpose. It worked. That no real world monarch ever was in this place is not relevant.
Finally, do not complete your hectoring by adding that editors take these rules seriously. You never know. If a writer has sold something with the very flaw you are complaining about, you are going to be taken less seriously.