Isn’t there an open source port of this?

Ah, ok, 99% chance you’re a troll. 1% chance that you’re deeply mentally challenged and it’s a miracle that you can type out sentences.

What if you refuse to bake a cake because you have no sugar?

No one with a brain is suggesting this. It should be up to the service and government to create rules to allow or not allow harmful content. It should definitely not be a payment processor.