I don't think so. The author of the blog projects their own view onto the situation. As they say, when they were a kid they took it at face value. So Greg could also draw the situation without inferring that he is being a twat.
It's the same idea as Dennis in It's Always Sunny in Philadelphia being oblivious that he's acting like a psychopath. Doesn't stop a lot of people from pushing a fan-theory that he is indeed a psycho and tries to hide it - which to me ruins the joke completely.
I'm not familiar with this book, but just the excerpts shown really mismatch the NYT quote in terms of their self-commentary.
The blogpost supposes that Greg is aware he's being a twat, and so somewhat mocks himself for it through the drawings and diary entries. I can accept (and even find it obvious) this applying to the NYT guy, but not to Greg. Greg just comes off even worse for this, not like he'd be ashamed about it at all. More like proud in case he is aware, or indeed oblivious, if he is not aware. This is because despite the blogpost author's assertions otherwise, I really don't find it a slamdunk conclusion he'd be self-aware about being a "twat", or that he'd understand why he'd be a "twat". On the contrary, the diary entries come across as quite the on the nose lesson in not being obnoxious (i.e. bad writing), completely upending such an interpretation.
I notice the word "literacy" thrown around a lot lately, in part by myself, but there's an inherent dishonesty to this. Language does not have absolute meaning, and you cannot read another person's mind. Just because you interpret literal works of art differently, I don't believe that necessarily qualifies you as illiterate. These are not the same qualities.
Just the other day I was discussing shows with a colleague, and I was convinced that by willfully skipping on large swaths of the medium, he lacked the genre literacy to "correctly" interpret various motifs. In the end, it turned out he actually experiences shows very differently to me. For him, self insertion is simply never a thing. It was a complete whiplash to figure that out, and everything made a lot more sense in retrospect afterwards. I still maintain he misunderstands the medium significantly, but I no longer see it to be a matter of a gap in literacy. It's a genuine difference in how the medium can address him. It becomes a difference in knowing what someone meant, and actually taking it that way. He can only do (and can be expected to do) so much to bridge such a gap.
I interpret critiques of this flavor and the "literacy" issue in general as being about a lack of interpretive range more than a tendency to produce some "incorrect" interpretation.
I think people are concerned that declining sophistication in readers actively prevents them from even being aware that some more complex interpretation is possible when engaging with a text. People read the overwhelming lack of nuance in internet comment threads as evidence of this. You can question whether or not that's a legitimate inference in isolation (I think it's dubious, personally), but, when bolstered by evidence from studies about how much people read for leisure, and falling grades on reading comprehension exams, I think the argument gains a little more weight.
I don't necessarily take the author as saying that these commentators are wrong about the NYT's author's self-awareness, but rather that evidence of a more complete reading would evidence itself in the comments if they had a more nuanced interpretation. There's a difference between flat out saying "wow this article really makes the writer look like a horrible person" and "I'm glad the writer had the courage to share this and seems o be growing but I'm amazed they were ever such a horrible person at some point in their lives". Again, it's probably unfair to make a judgement about overall interpretive ability based on one comment alone—one would actually need to subject the commenter to reading comprehension exams to know, but if you do feel the extrapolating judgement to population tendencies is legitimate, I understand why you might draw literacy conclusions.
The author can't really help herself either, sad to say. Losing the Tiktok habit would be a good start. But I get that that is like asking my parents' generation not to smoke cigarettes, or mine not to moralize intolerably.
Indeed, literacy is is the ability to read, and reading is interpretation. Interpretation requires context - of the domain, the culture, and the text - and resolving possible competing interpretations using a combination of charity and probability. Even the concept of "literal meaning" is problematic, because words don't mean anything by themselves; they requires disambiguation and contextual resolution of meaning. So really all you can have are more or less competent readings.
Pedantry is, therefore, arguably subliterate.
