Your final sentence makes no sense, I cannot figure out what you mean by it.
You reject premise 1), where premise 1) is: your utility function depends on them, i.e.”They are altruistic”. You reject it because you think any utility function with premise 1) is silly.
You reject premise 1), where premise 1) is: your utility function depends on them, i.e.”They are altruistic”. You reject it because you think any utility function with premise 1) is silly.