Is ethics/morality nonsense?

"To Conza: What is Rothbard’s definition of morality?

I seem to remember reading something (I’m pretty sure it was Rothbard) who said that when people discovered that there was a poisonous mushroom, they have established an ethic, don’t eat poisonous mushrooms! But doesn’t this just depend on someone’s desire to live? EDIT: If ethics are just commonly held morals then I agree with this."

https://forum.freecapitalists.org/t/inner-voice-or-public-logic-praxeology-and-ethics/11332/14

https://forum.freecapitalists.org/t/inner-voice-or-public-logic-praxeology-and-ethics/11332/38