> Do you wish to live in a human society?

As far as I can see, that is orthogonal to the issue at hand.

> all this law does is to impose the costs on those who incur it.

We might consider littering to be immoral, and might therefore feel that we have a right to prohibit others from doing it, but it does not follow that we have a right to prohibit people from using, selling, owning or manufacturing bags (or fine or tax them for doing those things).