Just because a character doesn't meet your expectations doesn't mean the author hates them.
Oda spent a lot of time on Whole Cake Island regardless of if specific readers enjoyed it. Oda's given Sanji a lot of panels regardless if those panels have been Sanji acting a specific way that pleases or irritates you. I don't know for sure if Oda likes or hates Sanji but I don't think Sanji's treatment post-timeskip or at any point in the series (since your reasoning is that Sanji's a 'simp' and I'm not sure when he first became that according to you, probably Enies Lobby or even the beginning) shows that Oda dislikes the character.
Personally, I can feel discontent with a character but saying the author dislikes them as if I'd know that seems a bit much. Oda's given Sanji plenty of panels that portray Sanji positively such as him saving his family and pretty much everything that came out of Luffy's mouth in Whole Cake in regards to Sanji so nah, I don't think Oda hates him but I can't change anyone's minds since the reasoning for Oda hating him is due to other reader's dissatisfaction with Sanji and I don't see how that relates to Oda's feelings on the matter in the first place.