Anbody who thought about it for ten seconds, actually.
If there's no objective pupose, that is, if life doesn't exist for any "why," then when we use the word "purpose" we don't mean anything real. We mean something we make up, but which has no correspondence in reality at all.
We say, "Well, I want to feel as if I'm here for something, but I'm really not, and will shortly not exist at all; so to avoid that, I focus on fooling myself by pleasing myself as best I can, and call that "my purpose."
And sometimes, we even try to dignify it by saying, "Well, who are you to tell me I can't have any 'purpose' I wish?" And, of course, that's irrelevant. Because shooting the messenger won't make a subjective "purposing" into anything more than self-delusion...if there is no objective purpose.