I dont think its the self loathing thing, its more like letting yourself die instead of trying to push through. Its more like a fall guy thing imo. And I think that is what Zoro or other fans have said or what is more generally called aura. Its easy to just sacrifice yourself and think it will solve the problem but when your mentality is to push through, survive and win at all costs, that is what takes real strength and courage. And you can see this in real world people too.
Look at it this way, its not a 1v1 example but in Batman, for Bruce to make the climb and the jump, the fear of dying was involved but here it is the will to live. And in this regard I think Law and Sanji are alike whereas Luffy, Zoro and Kid are different. I mean in this very flashback we see all the times Sanji is willing to die. Sacrificing like that is an easy cop out, yeah I did my job, now I can die or dying was me doing my job.
Contrast this with Zoro whose whole thing started from surviving that punishment and then going on to the nothing happened moment. Just pushing beyond his limits to survive so that he can achieve his dream. Even when was against the odds (Mihawk encounter) he didnt step back not because he accepted defeat and wanted to survive nor was he willing to die because he was sacrificing himself but because stepping back meant abandoning his dream.