That one line, "You've been by my side the whole time," is probably what set the insane fans into overdrive aside from the hand holding.
One thing fans forget again and again, is context. This always been at my side line, Naruto is referring to the current situation, as in she was by him the whole time since the ninja alliance arrived. Naruto was NOT referring to the whole series, if anything it was team 7 by his side the whole time, she hardly came in. Basically because Hinata being the copy leech as her development lead her, she basically served as a "storage" of Naruto's will and now just gave it back.
What about the hand holding? It could have been done for 3 simple actions separately or all together (most likely): 1. to thank her, 2. consulate her over Neji, 3. Kurama's chakra transfer was ready, who better to be the guinea pig?
The hand holding was important for Hinata but not Naruto, people are still angry at Hinata because she glossed over his death, no she really did, she was tearing at first but then just more "Oh Naruto-kuns hand," I'm sorry but why does it seem like Hinata makes regressions in times like this?
Could NaruHina become canon from 615 forward, possibly but still so much issues for characters and changing the story. If NaruHina did happen, Kishi would need to do something with Sakura to avoid damaging her character, only solution to Sakura would be for her to go independent not with Sasuke (all the wrong reasons again). Also Hinata cannot just be elevated in importance, if she keeps getting attention this risks pushing her into territory she does not belong in, mainly the team 7 and tailed beast conflicts.
I love how all the anti-narusaku fans try to make a massive case over 3 chapters and yet there is still so much more for the manga to do. I mean they act like Sakura is just going to be stored away or how its impossible for her to change. Do the insane fans always just take the words they see literally rather than looking for the context and meanings of the dialogue?

Yeah Naruto said he hates people who lie to themselves, but this is easily counter-argued with many other story elements and logic that more or less supports NaruSaku with proper consistancy related to story elements, parallels, and character attributes (basically Naruto and Sakura are not all what many anti-fans claim them to be, they have more good qualities to each other).
Given the mass trolling Kishi does, its funny how many fans give the arguments, "It was the real naruto who held her hand, not clones like everyone else," "Naruto thought it was romantic too, why did he grab her hand on his own will," "The sakura panel was basically Kishi signifying Sakura's time passed, she is no longer the heroine," "He held her hand longer so it was meaningful," "Hinata got the power first and Sakura got none so we win." Oh man these arguments are both funny and somewhat desperate as I see them, yes it was the real Naruto, how many times has the real Naruto saved Sakura now? He held her entirely, Naruto himself always saved Sakura not a clone. Yeah we did not get Naruto's thoughts on the hand holding, we cannot say his thoughts were romantic, if Naruto thought of anything at the moment, it was all the people who helped him and what Hinata and Kurama said, he was thinking of those who sacrificed themselves for him NOT ROMANCE. The sakura panel has importance and tell me this, if Hinata is the heroine now, what will she do when they meet Sasuke? All I would see between Sasuke and Hinata meeting is Who the f are you? See keeping Sakura out and doing this already overhauls a massive plot element, Hinata is not part of team 7 and never will be. The hand holding duration? Its a manga, these people should realize how much drama is put into these things and they extend the scene, it seems like the moment takes 5 minutes when its only like 15 seconds. He grabbed her hand on his freewill for many reasons (to thank her and begin the chakra enhancement plan). Hinata got it first and Sakura got none, yeah because Hinata was the closest, Sakura's overall powers would in truth be an unnecessary risk against the ten tails, but think of it like this If Sakura is left out from this, then something else should come her way. I'd still suspect Tsunade would give her the yin seal on her forehead technique via technique transfer (if Itachi could do it to Sasuke, Tsunade can do it to Sakura), or possibly a senju power up as many theroize by either Tsunade or Hashirama (thats if Hashirama sees Tsunade and being the apprentice, he gives Sakura that same thing merely from studying under her).
Still fanbases drive me insane when they just assume and not look at the greater whole or wait for the next portion of events.