I've noticed that the games that are labelled "girly games" are typically those that are perceived to be casual, easy games that don't require much strategy or commitment. My mind instantly goes to mobile games like Candy Crush. And let's face it, if you had never played Animal Crossing before, and someone told you that they spend their day catching fish and planting flowers...on the surface, it sounds super easy and mindless. That, combined with the pink/pastel towns you see all over the internet...well, anyone with outdated gender roles and stereotypes in mind could mistake Animal Crossing for a "girly" game.
Obviously, we all know that if you want it to be, Animal Crossing is anything but casual; in fact, I don't think I've ever encountered a game that requires as much commitment as the Animal Crossing series. And especially in New Leaf, with the ability to customize the whole town to your liking, the dedicated player can spend months playing for hours a day to get their town exactly as they like it...and then when it's finally perfect, they have to keep coming back every day to maintain it.
On first impression, yeah, I can see AC looking boring and repetitive and pointless. But oh, as you dig deeper, there is just so much to do. It feels like you're never done, there's always a new goal.