Hmm, it's just a figure of speach. "The most underrated feature" -> "I really like this feature and think it deserves more attention."
Just like "the best programming language ever" -> "a programming language I am really excited about, that fits my needs very well".
The hyperbole is not the problem IMO, it's the nondescriptiveness. I think the title should have something about exception handling in it.
The enforcement of the Guidelines has been pretty arbitrary, and quite often good (editorialized) titles have been turned back into something nondescript. Or now the other way around, the original title is editorialized to be less interesting. I think the most important criteria for a title are: does it get across the topic of the link, and the target page author's intention?