Because it is a form of learning.

Also ugly crying is not always a negative reaction. It's empathy which is important to our survival (and also wonderful).

All emotional reactions are "manipulated" - we choose to expose ourselves to situations wherein we might feel emotional reactions of various sorts. Why is art, "negative" reactions or not, any different?

As another commenter points out, it's a good way of learning - about yourself, how you feel, about other perspectives. It's also, hopefully, a chance to grow - reflect on your past, your mistakes, how you've treated others.

there are many things in life which cause crying which are not negative.

crying is absolutely not limited to “a negative emotion.”

if you’re struggling to imagine a crying situation that isn’t negative, i would heavily encourage you to indulge in more art.

I understand your question, and it is hard to describe. Our brains are pattern generators, and it "feels good" to resonate with patterns we've already experienced. Neural circuits create patterns by strengthening connections upon our experience. This is particularly true as we get older and our brains become less plastic. Lesser used patterns become harder to access as they are no longer reinforced as frequently. However, this feels less good for our brains, and we value novelty.

So in the same way that riding a bike after a long time is much harder than it is to ride one when you use it every day, you can generalize this to something like emotions. It is bad to only experience one type of feeling all the time, and variety is good. Having a controlled, relatable medium lead you to experience a less commonly-felt emotion feels good. I don't know if I can explain why--maybe we have mechanisms in our brain for encouraging this novelty--but this is likely why we seek out these emotional experiences.

I didn't believe "ugly crying" is about negativity. Rather, the "ugly" bit is about the abandonment with which one cries. One is so invested in the emotions (whatever those may be--it's not even a continuum of good/bad but rather a huge, high dimension vector space) that one abandons propriety and self-respect and just cries. It's about investment due to the exceedingly high emotional resonance with the subject matter.

This is my understanding. Caveat: I am not a person who cries much, if at all.

I lost my mom some years ago. It definitely just hit me, and I was kind of in an odd place in life at the time. I don't think I really processed it all well at the time.

Years later, when I watch a good movie that results in someone losing a parent figure, I'll often have quite a deep emotional reaction to it. But in the end I like these experiences. They help me look into those situations again and help me analyze the connection to losing my mom. Being in that state of emotion again helps me process it now that I'm in a very different stage in life.

Because art can be seen as manipulation, or it can be seen as tapping on the deeply fundamental hooks that make us human. Feeling affects from an artistic representation tells us something about the human experience that goes beyond our intellect. Its closer to something spiritual rather than something analytic.

That’s where the confusion is; it’s not a negative reaction. It’s an intense emotional reaction, sure, but not inherently negative or bad.

You’re not being well understood here, but I do this too, and have done — with everything — all my life.

The answer is ultimately that if you deconstruct and logically analyse any particular human activity it either ruins the fun and/or makes you realise how primitive and dark most forms of entertainment are. People like being emotional, for whatever reason.

I like the explanation that says it’s about learning, though. Learning somehow feels intrinsically good.

It might help to compare it with going to the gym or for a run. In some sense this produces an immediate negative reaction: our muscles get sore and stiff, and we get out of breath. But we still do it perhaps because we feel better afterwards, or because it helps our long term physical health.

Likewise, deliberately experiencing sad (or otherwise) emotional states has both short term and long term positive outcomes. In the short term we feel a sense of catharsis, and perhaps reassured that our feelings are relatable. In the long term we feel more in touch and less overwhelmed by our emotions.

It's not negative to be moved to tears. And it's not manipulative to watch a tv show. I don't think you're decontextualizing as much as you're trying to adopt some alien contrarian viewpoint.