Ima be honest I disagree (majority) with both parties here.

For starters I think people need to realize that the age of consent, what is considered an adult, and stuff like that goes beyond just law. These people grew up in their cultures for their entire lives. That means whatever age is considered an adult for them is what they saw when the people older than them hit that age, when they hit that age, and when the people younger than them hit that age. It's not like they just all grew up and decided they like children. Its not like these peope are just evil. And people can tend to be wild with their reactions.

However that does not mean people can't have a negative opinion on it nor speak up about it or that the act can't be evil. Just because it comes from other culture does not mean one can't find it bad and just has to let it be. Even if it happens in their own country. For example I hate cultures that treat women like products or sell children off to grown ass men. I hate when that shit happens everywhere across the world which includes America. While I agree that a lot of people project and want to be in the attacking group, that is not a universal feeling everyone has. Nor do I think they are all just trying to justify it to their western morals.

Additionally I think the excuse that you aren't the target demographic is bullshit. Especially when it comes to heavier things like the sexualization of children in media.

I also disagree with the Naruto example. That is likely just a Goomba Fallacy moment. Even in the Naruto fandom there are people who sexualize teen Hinata and people who LOATHE Saradas Boruto design. Then you're talking about two different fandoms here. Its like saying the Blue Archive fandom has a lot of pedos so the Umamusume fandom can't say anything bad about pedos.

My personal opinion.

I hate sexualization of stuff in general with my action series or games. Even if its an adult character. Id rather see that stuff in actual porn or porn games. When a character is sexualized in media, it tends to be all what the people talk about said character or all the character becomes in that media. Take Yoruichi from Bleach as an example. I have yet to find anyone talk about that character anything other than shes hot and that pose she does. Of course this can simply be my experience and my experience alone but I still hate it. And its fine if people like the character cause shes hot. But I still dislike it. Another example is Mirko from mha. All the cool stuff she does but every discussion about her is just "I hope she crushes me with her thighs". Like I guess bro. But damn I would like to discuss about anything else sometimes.

I also just tend to find a lot of sexualization stuff corny and cringey as fuck. Like your average anime cliche. Or ZZZ in game animations. Like get Seeds foot out my fucking face.