Having an ethical outlook is a great idea. And it's good to criticise ideas you think are unethical.
The point of the post is that just because a person presents an unethical idea doesn't make that person universally unethical. The point is to separate the ideas from the person presenting them, so that people can feel free to present novel ideas without fearing damage to their reputation if the ideas are unpopular.
The point of the post is that just because a person presents an unethical idea doesn't make that person universally unethical. The point is to separate the ideas from the person presenting them, so that people can feel free to present novel ideas without fearing damage to their reputation if the ideas are unpopular.