I don't think it's the kids being able to handle it so much as it would be the parents freaking out. Coming from a teacher's perspective, parents can be stupid.
But in 1991, they made action figures for Terminator 2: Judgment Day. I had some. And I saw said film when I was 7, on rental. Likewise, few years later, I recall they had figures for some Stallone film, either Demolition Man or Judge Dredd. I'm sure there are other examples as well. And those where outright rated R. So figures for a hard PG-13 isn't exactly reaching.
True, but since those films were rated R, parents can "control" that a little better (in terms of what to take their kids to see). However, Batman is a little different. Batman, being a comic book property, has been more "family targeted" in the media than times that it has been for "mature audiences." Granted, he is a darker character, but even more-serious depictions of Bats have been tame (Even Batman Begins
, although, I will admit, that little kids probably would be bored with the first half of the movie). General audience peoples who don't search the internet on the latest movie buzz like the good folks at the TrekBBS here, will probably think "Oh, Batman. Should be good fun here."
Hmm...I don't know if I am making sense...so, in summation, I have an equation:
Toys + PG-13 rating + movie that early critics are saying are not for kiddies = Captain Craig
being annoyed during his viewing of TDK.