for children vs. for adults

Hay guys how come in Japan it's acceptable for adults to read manga but anime is strictly for children (or teenagers at most)?

It's really the same content, right? What the fuck difference does it make if I watch the Azumanga Daioh anime or read the manga? WTF. ZOMG.

No, seriously.

I would never through my manga, magazines or books away, that's just stupid.
I like to build a colection