Wait, I'm not quite sure what point you're trying to make here. Is it that I commented about Paul Graham's writing style in response to a PG essay on writing style? Is that "making up concerns before even engaging with the author's ideas"? The whole point of the essay we're discussing is writing style, and in particular a set of suggestions he has based on his own work.

It's valid to criticize someone for not giving a piece of writing a charitable read before criticising the author's style, but that does not seem to apply when the topic of the essay is the author's style. Writing style is largely about figuring out how to direct the reader to your ideas, so it seems axiomatic that any piece of writing that needs a high-effort charitable read is poorly written (this, by the way, is in TFA).

As to your original point, being too vague also doesn't increase signal to noise ratio. It just lets you write as though a lot of noise is signal.