Didn't Kizaru mopped the Sabaody's floor with all the SH's, including Zoro? Was that not an L as well?
Rayleigh literally saving him is a W?
And then Kuma showing up again and sending them away while none of them, again including Zoro, couldn't do shit, again?
Best Zoro could do at TB was a sneaky attack and then he was like "plx, no kill luffy. you too strong. me too weak. kill me instead."
How the hell can't people see that was a L for Zoro? All the SH's were already at their limit after the Moria fight, and then ANOTHER Shichibukai, one with an even more annoying power, comes in and basically just finish them. What's the matter in taking a L in this situation? Zoro is not going to be a scrub for losing in that situation. Just calm down and accept his defeat.
Zoro's declaration of "not losing again" was a moment he came to terms with his own weakeness, and accepted that he still had a long way to go before being able to defeat Mihawk. Which is way it was important that his main fights were about him getting stronger, learning new techniques to include in his arsenal, so that, one day, he could best Mihawk. But you shouldn't take it like he is literally never going to lose again. He lost in Water7, he lost in TB, he lost in Sabaody. And yet, after Sabaody, he again realized he was too weak, but by that time, instead of asking Mihawk to train him, so he could beat Mihawk himself, he did to become strong enough to help Luffy become Pirate King, throwing once again, his pride aside for his captain.
L's are important to a character's development. Don't know why you people get triggered so much about this subject.