It is a key statement that we have free agency to choose our paths, and that is why we praise some actions and people and blame others. Otherwise why would be concerned about determinism and say that it is better to believe supernatural religion than to be a determinist?
Do you think psychological hedonism is incompatible with agency/free will? The only people I have seen making this claim are arguing *against* psychological hedonism. It seems like a straw man.
I will qualify my position slightly. I don't believe it is impossible to pursue pain. Only that someone who did that consistently would be dead, in prison, or in a mental institution.