It could be because the manga's content is very intense and evokes strong feelings. Maybe the story or the art style has a powerful impact on them.
It's a rather niche and specific theme that attracts those who have a particular interest in such intense and explicit content. But it's not for everyone's taste.
Maybe it's because they have a strong bond and feel comfortable being themselves. There's no need to hold back in that kind of friendship.
Maybe it's because the plot demands them to be upfront and honest. They might have a personality that doesn't hold back naturally.
It could be because the story has a tragic plot or deals with difficult emotions. Maybe the characters go through tough times that readers can relate to and feel sad for them.
One reason could be that the characters' experiences and struggles resonate strongly with readers, making them feel the hurt along with them. Also, the art and narrative style might draw people in so much that they become fully immersed and vulnerable to the emotions portrayed.
Maybe it's because the story touches on some deep emotional issues that resonate with them.
Some people cry when reading manga because the storylines and character developments are so powerful. It might bring up memories or feelings that they relate to on a deep level. Or it could just be that the art style and the way the emotions are shown are so compelling that it triggers the tears.
It could be that the storylines or characters don't resonate with them, making them feel disconnected and powerless.
Maybe they don't like the plot or the way characters are developed.
There could be various reasons. Sometimes the story might resonate with their own experiences, causing strong emotional reactions. Or maybe the art style and the way the emotions are portrayed in the manga are very powerful and trigger the lying and crying.