This.
The point isn't to have superhero-movie FANS only reviewing the movie. The point is to have someone who can make a fair assessment of the movie.
"I hate all movies of this type" isn't a fair assessment, and "all movies of this type are equally bad" isn't a good analysis.
It's more useful for a critic to be able to sit down with a genre and say, "for this genre, this movie is..."
I expect it of critics of horror movies. I expect it of critics of westerns. I expect it of critics of romantic comedies. If I'm reading the review, the chances are really good that I already know whether I generally like that genre and am even considering going to see the movie based on that broad knowledge. What I want to know from a critical review *IS* how a movie stacks up against others in its genre, and perhaps whether it does things that are surprising for its genre.
I cannot actually believe that there is almost anyone in the audience who reads reviews of movies thinking, "gosh, I just don't know whether I'd like a romantic comedy movie -- please tell me whether the romantic comedy genre is worth my time, Mr. Critic!" People know what they generally like or dislike.
A really intelligent review could make someone who thinks they don't like the genre check out the movie anyway. (I hate horror movies, but I've been at least tempted by
The Cabin in the Woods thanks to reviews, which I read because I was just curious.)
But I'm really tired of reviewers who feel they have to be Crusaders of Taste. "I don't like this type of movie AND NOBODY ELSE SHOULD EITHER". Blah blah don't tell me what I should or shouldn't like. It's my $15 and my 2 hours of escapism.
Pfft, well, you notice that "fangirls" are completely invisible in these reviews. Apparently the only people who could possibly be lifelong comics fans or be exciting for this movie are boys.
I suppose we should be grateful. At some point critics will discover the existence of fangirls and then we can look forward to loads of condescending bull****, too.