Warning: overexposure to moe may cause moe tolerance to develop! Soon, you'll require more and more ridiculous moe tropes to satisfy the cravings!
Anyway, I guess I look at it this way: I don't expect Gurren Lagann to realistically depict physics; I don't expect Kanon to realistically depict personalities. That's why it's fantasy. Think of it as Platonic ideals of a portion of reality.
That being said, it's also probably true that most male authors have trouble writing realistic female characters, and the way that they are presented in these works probably says as much about the male authors as it does real women.
Incidentally, the K-On! manga was also written by a man.