The first was of trying to push the other writer into a genre into which the work didn't fit. This really showed when the reader/commenter didn't know the genre in question. That was when they tried to push the work to becoming their own writing or the writing of their favourite writer at that time. I've had this happen with editors (once with fiction, once with non-fiction), and it's not a good thing. The story the writer is telling is their story, and the flaws in the telling need to be resolved without destroying the quality of their writing.
If I were teaching these writers, I would be telling them (very strongly) that they need to read far more widely. They need to read carefully, with an eye to understanding the craft that supports each and every work. Storytelling can be done in so many ways.
The second was of recycling advice learned from others without having determined first that it was relevant. "Telling not showing," for instance, is not a useful piece of criticism when the section that is being told is a minor plot point by a minor character, for instance, and showing would take the story away from its main paths and lose the reader down by-ways. Nor is it showing through action useful when the story is one that requires description or neat character summaries as an aid to interpretation.
There are times for telling and times for showing and blanket rules are a nuisance (but necessary at a certain stage of learning - this is why writers are in trouble if they learn a little and then say "I am beyond this now" and never move beyond the learning they think themselves beyond).
Genre matters. The story matters above everything. If there's no fault, then trying to fix it because the story doesn't fit the rules one has been told is really, really daft. If there is a fault but you can't work out what it is, then falling back on a rule told to you by someone else only works if the fault would actually be fixed or the narration improved or the characterisation made more intense by the application of that rule. Maybe one case in ten of the comments I skimmed through this morning would have been improved by the application of the rule cited in the comments. In all other cases, it would not. In some instances, it would have made things worse.
My set of rules for critiquing goes something like this:
1. What genre (and, if possible, sub-genre) is the best fit for this work and why?
2. Are any of the problems in my reading due to going off-genre? If they aren't then genre matters are fine at the editing level.
3. What is getting in the way of the plot?
4. What about the characters?
5. What about stylistic issues?
6. If scant worldbuilding*, or dangling participles or a cliché** or sentence fragments or telling-not-showing are causing problems with 3-5***, then they should be noted in this context. If they don't cause any problems at all (if they are intrinsic to the style, or magically clever in how they achieve strange and wonderful depths to the tale), then I'm wasting my red ink, even if I personally hate the cliché used or the level of worldbuilding and am tired of dangling participles.
Now the papers are gone and the mess is less, both in my mind and on my couch, I shall return to work.
*Which can be insufficient, or it can be amazingly poetic, or it can be a number of other things. It's not the amount of world building that appears in a novel that's the problem, it's how the novel handles it.
**The example I have in mind for this is where a writer had one single cliché in 50 pages of prose. If the cliché had been egregious and took the reader out of the novel, that would have been a problem, but it being a cliché is not actually necessarily a problem in itself. Clichés depend on context, and the comment addressed the cliché and not its context.
***Or any other crucial aspect I haven't listed - I'm not trying to be exhaustive here. In fact, I'm trying very hard to make these notes and then get back to editing.