The following excerpt is from an article of Harry Frankfurt who is a professor from Princeton University:
Especially by pretentious word or deed: There are two points to notice here. First, Black identifies humbug not only as a category of speech but as a category of action as well; it may be accomplished either by words or by deeds. Second, his use of the qualifier “especially” indicates that Black does not regardpretentiousness as an essential or wholly indispensable characteristic of humbug. Undoubtedly, much humbug is pretentious. So far as concerns bullshit, moreover, "pretentious bullshit” is close to being a stock phrase. But I am inclined to think that when bullshit is pretentious, this happens because pretentiousness is its motive rather than a constitutive element of its essence.
I know that "so far as something is concerned" is an idiom which means " in considering something". But what does "so far as concerns bullshit" mean? Is it the same as "so far as bullshit is concerned" which means "in considering bullshit"?
I am not sure what "this" in bold refers to. Is it "when bullshit is pretentious"?