> A single word or a short phrase may be enclosed in quotation marks to indicate ironic use.

Normally, yes. But the primary use of quotation marks is to quote - in a direct response to something someone wrote, you come across as either dishonest or stupid if you claim to be using them ironically.

When I read gergles's comment, it was clear to me that he was describing a class of sentiment, and not directly quoting who he replied to. The manner in which he did it is, to me, idiomatic English.