My thought is that maybe heroes in those genres don't get accuses of Sue-dom as much because it's sort of expected that your Jason Bourne or Sherlock Holmes be super smart and competent and have approximately one billion obscure skill sets to pull out of the air at the last minute for a climactic action sequence or criminal reveal.

So likewise romance characters don't get as much flack for being dishy and experiencing love at first sight either, because again, it's an expected trope of the genre.

(More flack than espionage characters, though, because romance is a giiiiirly genre and therefore silly.)

Just my first instinct though.