Welcome.
As for your post, well, I just want to add this.
Ever notice how Naruto was mostly shocked by what Sakura said and actualy believed her UNTIL she mentioned Sasuke? That was the button push. He only called her a liar after she mentioned Sasuke. Not after she confessed she loved him, not after she said said she wanted him, but after she said she didn;t care about Sasuke anymore.
Naruto's "Goku Button" is Sasuke.
However, DrK does have a point. It is all pointless now since any purpose, if there was one at all, is thrown out because of two very big reasons that people seem to forget.
1) Naruto lied to Sakura first. According to the Last movie, Naruto only "loved" Sakura because of his rivalry with Sasuke and Naruto never understood love...so, yeah, Naruto is a manipulative bastard of a hero who uses people for selfish gain. Unironically, they still blame Sakura for being a horrible person. Meanwhile, ironically, Kishimoto said if Sakura moved on from Sasuke she would be a terrible woman, but apparently they already see Sakura as a terrible woman with or without the confession scene.
2) Retcons....retcons everywhere.
I think Naruto realizing something is wrong with the Sakura's confession, it's not only because, Sasuke is his Goku button, but Sasuke was also Sakura's Goku button to an extent, so Sakura out of the blue saying stuff like she doesn't care about Sasuke anymore and wanting Naruto to stop chasing him is enough for Naruto to know something happened, and makes him distrusts the whole confession.
It's like Naruto face reactions show he is hearing something he can't believe in a good way (Sakura saying she loves him) followed with something he can't believe in a bad way (Sakura saying she doesn't care about Sasuke anymore). It explains why Naruto thought she was lying to herself.
It is ironic really that Naruto that accused Sakura of lying to herself, when he was the one lying to himself all along, so him saying he hates people that lie to themselves is basically self hate in Naruto's case.
but The Last movie was just a giant retcon so technically there is only 1 reason everything seem pointless- retcons