What is he saying? He is saying people know. They know what is right. They know that there is a God. He has shown it to them. If they claim they do not know, they are lying; they are simply remaining willfully ignorant of that, and He says they have no excuse.
So they do not want to worship God because He places restrictions on them. He places responsibilities on them. They ignore His law. They ignore all the ways that He has shown that He is there and He is enforcing His way, and so God says they are without excuse. They have done it to themselves.
