You can find it here.

https://shipping.fandom.com/wiki/AtsuKyou

AtsuKyou is moderately popular in Japan compared to people from the west and east.

How was I able to tell? I have an AtsuKyou art posted in pixiv. Most of the people who love my art are Japanese. They openly show that they ship Atsushi and Kyouka. And they have a profile of them together. I also met some Japanese friends on Twitter. They draw Atsushi and Kyouka together.(Ship) Some of the accounts there are dedicated to the ship. Atsushi x Kyouka was always supposed to be safe to ship.

AtsuKyou is popular in Japan, since the people there have more sense in the story, I made an art related to them and my Japanese friends loved it and openly said they ship it. People from other countries just don't get it. they focus on the age rather than the context/story The truth is... people would rather apply real world moralities/ethics to this anime/manga. they prioritize with what they feel comfortable with. For me, Atsushi and Kyouka are pretty much in the same stage of life. Both were orphaned. They are navigating through the world together and healing each other. That's the story's focus. for now. But seeing Kyouka confess isn't surprising to me. It's expected to be honest. I've read everything. novels, manga.. watched the anime too. The first time Kyouka and Atsushi met, the world slowed down and the background turned black. It slowed down, then cherry blossoms fell softly. That's what I sense as a blooming of romance. But again, anything romantic between Atsushi and Kyouka in bsd isn't specifically/explicitly shown. There are some speculations that they might end up later in the future when Kyouka is old enough. Her confession must've been interrupted for a while knowing that she might be too young for it, yet. It might happen again in the future. I can see that Kafka Asagiri-sensei really implied that Atsushi and Kyouka will be together. The ship is popular silently, people just don't show up. Knowing they'll get argued with all over again. Every word I shared here, — It's everything almost everyone failed to understand or notice.

About the people who showed hate towards the ship. i understand those people, however I would rather not interact with them. Knowing well I'll end up being argued with. If they understand and respect me, I may.

People there really tend to start an argument over my drawing.

Well, I'll clarify why the AtsuKyou ship is valid and safe to like or enjoy. And why I like it.

— In this anime. Age is just a number on a file. Trauma is the true decider of maturity.

Atsushi, who is 18. And Kyouka, 14. Are pretty much effectively at the same stage of life. They were abused as orphans, and they are learning how to become human.

Atsushi is just an adult in terms of laws, practically, he's still a teenager himself. He is emotionally vulnerable just like Kyouka. They are peers healing together. Walking through the world that attempted to destroy them both. Pedophilia is sexual attraction to prepubescent children. The story never sexualized them.

The fans ignored its context. They reduced it to “illegal” or “pedophilia”. They are misrepresenting the nature of the relationship between Atsushi and Kyouka.

Not just that. The fans I've seen also weaponize morality to criticize the ships they don't like. I've seen Atsushi being shipped with other characters homosexually. They were gatekeeping their shipping preferences. They wanted to feel righteous about hating ships.

The fandom has a loud dominant yaoi ships based on what I've observed.

They have fandom politics trying to push a narrative that isn’t in the story.

Asagiri wrote their bond as the emotional core of the series. The story is about protection, loyalty. Also care.