Let me try to take those questions one at a time:
If wallet providers require authorization from the government, isn’t it centralized?
It’s regulated, not centralized. Similar to the Internet.
Also isn’t this based on Ripple, so shouldn’t I just be able to send ripple from one payment pointer to another?
Interledger is not based on Ripple. Some participants choose to do the settlement in XRP, but that happens off the Interledger network.
Why doesn’t Coil allow payments in ripple or any other currency?
I’m not sure, someone from Coil would be better suited to take this one. @uchibeke maybe?
Also I heard ripple is effectively centralized, is this true and doesn’t it effect interledger?
No idea. But either way, it doesn’t affect Interledger.