It already is? It’s not a religious problem, it’s a third world country problem. People just have more important things to worry about than plastic littering but I agree it needs to be changed.

There should be prohibitions against plastic bags in general but there’s no caliphate now, so it’s not a monolith that sets the rules.

Edit: i would also like to mention that a lot of third world countries do not have the system to recycle or process plastic waste. Even if you hand them over to municipality, it gets thrown into open waste dumps and get burnt.