Well, since "search for bin Laden" is not a book title, then HG must have meant that he was quoting somebody else. That is why they are called 'quotation marks'.
See, I put it in quotes, because I was quoting HG.
I put " 'quotation marks' " in single quotes because I wanted the reader to consider those words as in combination, as a single thought. The I put the phrase in quotes in the latter sentence because I was quoting myself.
Grammatically specking, there is no such use as "scare quotes" for that punctuation. Of course I used quotes here, to show that other people do use the phrase "scare quotes" to justify the improper use.