“It looks like? Could you nail that down for us? Is anything certain in your ivory tower”

It’s a figure of speech, are you so lacking in good arguments that the most you can pick on is the use of a figure of speech?

Surely one who presumes to give another a grammar lesson should actually know something of said subject. This ‘teacher’ fails on both parts.

Addressing the first point: The stylistic ‘hedging’, or, if one prefers, the issue about clarity, pertains to an area considered on the fringe of grammar, if concerned with grammar at all. Traditional grammar advice relating to improvements to structure depends on authorial intent; hence the provided suggestions (which would change meaning) aren’t strictly grammatical changes alone. Readability isn’t compromised by the original phrasing anyway, but the perceived inadequacy of a writer’s research doesn’t come under the banner of grammar at all. Without even considering academic categorization, one must consider that advice of an editorial or journalistic nature do not fall properly under the subject of grammar as most would understand it.

The “mouthful in the subtitle” advice betrays a lack of understanding in our ‘grammar teacher’. The clause addressing the ‘mouthful in the subtitle’ denotes – clearly, to most readers, I would imagine – the fact that understanding the exact subject, and hence how one might categorize the work, might be troublesome; the second clause elucidates the contextual meaning of the first. We could re-interpret this: “the subject of Book A is incredibly specific, but no doubt it relates closely to the subject of Book B”. Whether a comma should be present is pure Oxford-vs-Cambridge-convention pedantry.

There is a point about medical costs which appears well made. In my opinion, this begs a polite clarification from the author and no more. Of course all readers understand by now what they are dealing with grand-standing in the name of grammar anyway – but more of this level of competence in advice helps readers suspend disbelief that the attack is unwarranted, or motivated by other things.

I could go on, of course, but I think my point is made: if one is going to use passive-aggressive techniques of insult (such as grammar correction) toward people with whom one disagrees (or has disagreements, perhaps? – we, the intelligent readers, know the difference), one should be sure that one is actually good at grammar first.

Now – away from the ‘one’ of generalization –
you*, in this instance, dear ‘teacher’, word your subject so clumsily as to suggest that we (the readers in general) could all learn from your lesson – but I haven’t been schooled by your remark in anything accept your apparent inability to tackle an issue honestly, head-on. Your use of the vernacular in the opening complaint makes plain the pretense of your corrections, but couldn’t your response have been… well… better?

If you are going to be pedantic as a vehicle of disrespect (and that alone, so far as I can see, for I couldn’t infer any love of grammar from your writing) at least ensure that you are up to the task, or else expect the same disrespect yourself.

Finally, if you, ‘teacher’, are going to be so willfully narrow (‘narrow’ here is interchangeable with ‘unforgiving’ or ‘dull’) with your interpretation of what someone has written, then at least apply the same standards to your own writing.

To you, ‘teacher’, who writes: “The second block quote similarly is about legislation, with the supposed harm only hinted at” I will leave the final lesson – the lesson of which two glaring grammatical mistakes you made in that sentence of yours alone!