Imagine you're at a Casino.
You bring USD, which you buy chips for.
You spend a couple of hours playing, and at the end of the night you've gotten lucky, and tripled your money.
You sell your chips, and get USD back.
The Stellar network is what happens when you're dealing with the chips:
- You can give chips to people
- They can give chips to you
- You can trade different types of chips with people
Getting money in/out is the sole responsibility of anchors.
Ergo, KYC/AML is done by the anchor. The network itself is completely unaware of any of this.