You can both believe that there is no objective morality, and think that if objective morality existed then you should follow it. my criticism is - he saying that if objective morality existed and you dont like it, you should ignore it. thats not logical.
This is not addressing my criticism. He is saying that if objective morality existed and you dont like it, you should ignore it. I am not saying that objective morality exists or not, but addressing the logic in hypothetical world where it does exist.
Use sufficient intelligent AI to find objective morality. If it exists, if it makes sense. It will have better understanding of it than us. Of course, if that sufficiently intelligent AI doesn't kill us all prior.