I think art, including poetry, is about moving an audience one way or another, to get some message to them. Art can be about self-expression, but it doesn't mean everything morbid is a reflection of the person. I'd ask what the person making morbid art is attempting to do and how successful they're being.
When you show it to other people I'd wonder why you're doing it. Is it to see who shares your interests? That's okay, I think. People have interests in lots of things that could be morbid while still being balanced mentally. There's a difference between an interest and an obsession. Is it to get technical feedback on your artistic skills? That's totally okay. Is it to attempt to shock people? That could be okay, if you're doing it because you think your audience needs some kind of shock (like say, if you think people are being apathetic about a war), but if you're doing it so that you can become someone-who-shocks-people then that's really more an ego thing.
My own personal tastes are not for overly morbid things generally. I like Halloween and forensics shows, but I don't like movies with gore or downer endings. I also don't really care for "self-expressive" art. I don't think it's as good because it's not really made for an audience. I mean, it can be, but if someone's goal is "I want you to know how I feel" I'd respond with "Why?" It's the why that matters to me, and with morbid stuff I feel like 2/3 of it either doesn't think much about the why or it's reasons aren't ones I care for.