Did we read the same chapter? Shanks only attacked because his observation futur sight showed him Kid was gonna kill people and cause many casualties, he cared if he still injured from wano war, so….he value life from any era. the only thing we know for sure now, is that we never saw Roger fight because Shanks fight exactly like him, so Oda kept this to the end, we gonna see more Roger technique in shanks style.
Actually, for Shanks to ask if Kid was good to fight may have had different meanings.
It could have been a sign of good will. As in Shanks does not want to fight an injured person because it goes against his morals.
But it could also have been a sign that Shanks cares about his ego a lot. He might not like to fight someone injured because it would harm his reputation or at least not further it.
Is it not also odd to say the least that the fleet of redhair out of all possible people is considered so weak? People would naturally be inclined to believe that this is because he is the defender of the weak or something along those lines, but such a fleet is far more suitable for someone who aims to become god and wants to get rid of competition. You can protect all the weaklings in the world because they pose no challenge to you, you can also keep the strong ones with loyalty to you and then crush anyone else.
Shanks has way too many good relations with people that we know are of good character. Whitebeard, Dory and Brogy, Mihawk, Luffy. He never showed any real signs of being a villain so far. He stepped in to stop an incoming slaughter at marineford, he stepped in when the three rookies at Wano were about to be attacked by an admiral.
He did meet up on-screen with the gorosei, but to what end were we shown this by the author? There are plenty of reasons to talk to people in positions of power other than being in cahoots with them. Like negotiations or attempts to use them for his own ends.
But that is precisely the issue, shanks is a character who has not gotten much time on-screen. He is kept rare, so that he is not devalued. Every time he is supposed to show up in any chapter, the audience is supposed to go crazy over it. Even if not much happens. Which is not to say that nothing does happen when he shows up. But it is definite that even if nothing happened, the effect would still be the same. That is just the effect he has in his role as an enigmatic character. The same for Dragon, or Kaido before Kaido ever appeared before the audience.
If people believe in Shanks to be a good guy, it makes sense alone from how the story has always played out thus far. Characters do not change from good to evil, unless it is pretend-evil, like with Nami in Arlong Park. But they do change from their role as evil antagonist to neutral or even good or to a point where the audience can sympathise with them a bit. It would be 'out-of-character' for Oda to turn Shanks into the equivalent of Aizen from Bleach.
But then again, look at Shanks actions and the body language. He is ruthless. He may not strike the audience as 'evil' because of all his relations to characters with moral code and coming off as having his own. But a character does not need to be evil evil. Just having their own motive can be enough for them to commit to actions that can make them a major antagonist. Look at Mihawk. He is apparently stronger or as strong as a Yonko, but he does not have an impetus that makes him strive for that title. This makes it clear that Mihawk is a neutral character, neither good nor evil in any sense. So what about Shanks? Not only is he a Yonko but he also is actively pursuing the One Piece. This means he has a clear goal.
He supposedly sacrificed his arm to bet it on the new era. He shows up repeatedly to help out the rookies. Even in Elbaf, you see him with a Giant kid, so ask yourself this, which 'era' is he talking about? The entire chapter in Elbaf was a major red flag because not only do you see him destroy kid's crew even after they had already surrendered, which no clear cut good guy does unless the ones who got clubbed were shown beforehand to be worthy of such treatment, such as Orochi in Wano. But the main indicator is the Giant kid.
It comes off as an innocent callback to the meeting between Luffy and Shanks, but when seen in the context of all the previous actions of Shanks we have been shown so far whenever he came up, it puts all the previous statements by Shanks into a completely different, new context. A context wherein Shanks is grooming pirate rookies.
For example, as mentioned, Shanks saved Law, Kid and Luffy at the end of Wano, talking about cutting the rookies some slack, only for him to crush one of those same rookies he stepped in to protect from an unfair battle right afterwards. This makes it clear he didn't step in to save the rookies at all. He stepped in to prevent an unfair battle, likely also for luffy's sake and probably also for political reasons.
Before that, he talked to whitebeard about betting his arm on a new era, specifically referring only to luffy and no other rookies. Yet look at how he and the Giant kid interact. The callback to the beginning with Luffy is very obvious, no? But why is that, if Shanks truly believes Luffy to be the one to bring about change in the new era that Shanks speaks of? It makes you think that the Giant kid may be one of those who becomes a hero of the era that may follow Luffy's. But that is not what Shanks was talking about when he made that bet. And he is not being shown to have made any other similar 'bets' for this Giant kid. The scene is not a full parallel, just a simple reminder of the beginning of One Piece. He was 'just passing by' after all. So what made him get carried away and stay longer?
Also think back to Marineford, where he did not step in for most of the fight. When exactly did Shanks step in? Specifically exactly in time and place to save Coby from being Akainud.
Shanks might feel that he is carrying on Roger's will now. He did not want Ace to get defeated by Teach, but neither of those two points mean he is necessarily a good guy.
Shanks very obviously has a strong emotional tie to Roger, be that positive or negative. Who, just as a reminder, teamed up together with Shanks with the marines against the Rock pirates. Luffy reminds Shanks of Roger. And Shanks was not a full grown member on Roger's ship. Shanks was just a kid, just like buggy. Yet Shanks now constantly refuses to take such people onto his own ship. A bit odd for someone who some would think is trying to carry on roger's will.
Remember that scar Shanks has? From Teach? How did he get it? You'd be inclined to think that Teach attacked Shanks, right? But when Shanks arrived at Marineford, Teach didn't pick a fight with Shanks because he knew that he was no match for Shanks. Considering this, would it have made sense for Teach to attack Shanks to inflict that scar on him unless it was in some battle between the whitebeard and the roger pirates? Shanks has been seen to be envious of Teach since they first met, whereas Teach showed no interest in Shanks at all. So who would have picked a fight with the other in your opinion?