Simply because feelings fluctuate.
You couldn't blame the rosette for liking, no, loving all of them. You really couldn't. You also couldn't say she was fickleminded. You really couldn't. They fell for her at their own pace. Or her for them, at some point in time. But these feelings were ephemeral; fleeting. She was in pursuit of true, lasting love.
Ikuto…
Tadase…
Kukai…
Kairi…
Nagihiko…
Five awesome guys, with five awesome personalities.
They had all also kinda liked her at some point, and she, them. But being an elementary school student, those adults would pass it as hormones…? Well, she really didn't know. Or care, for that matter. (A/N: Add in echoes of "Cool & Spicy!" here…)
That's our Amu. The confused, lovable, and shoujo-ai heroine. That we all (pretty much) love.
So why is it that the guys liked her?
Was it because she was…
Hiding behind a mask? (Cool & Spicy)
Popular with lots of fangirls?
klutzy?
With really weird pink hair?
"THE LEGENDARY JOKER~!"
She also didn't know.
Why did she like so many guys, why was she so fickle?
I think, dear reader, our favourite rosette has gotten her answer: simply because feelings fluctuate.
I really think Shugo Chara was made to show how 11-year-olds can fall in love with so many guys. Seriously. Peach-Pit really got her involved with so many of them. -_-" Jk, but Amu should really stop being so fickle. Personal opinion. The girl needs to choose! And that's why I wrote this.