That reason is that Emo people listen to it. Emo people are those who like to cut themselves (usually) or just hate their lives. They are easily depressed and wear normally dark clothing. More-so it's just a form of depression and in some cases, bi-polar disorder. But that's aside the point.
Emo can be defined how you see it. Emo can be someone who's overly happy, a person who is very moody, or someone who's always one specific mood -take depression for example, so that proves my point. But the common Emo is the one I stated before now.
If you ARE a cutter Emo, please seek help, it's not good for you or anybody else's health. Talk to somebody -a friend, a parent, a teacher, someone who will listen- to get advice on your life and decide if it's really that horrible.
But overall, there isn't much a TRUE definition for the word "emo". It's all about how you percieve it, so don't get too confused. And when I say that, I'm referring to modern times, not anything else that's happened in the past.
My examples are a little extreme; don't take them too literally. And don't try to change yourself to be an Emo in any form just because you want to be like somebody else. You'll only appear like a poser, so just be who you are.
Emo Kid: My life is a wreck. I wish it would just go away.
Normal Kid: Aww, don't be that way, cheer up a little!
An example of Emo Rock (Songs with depressing lyrics)-
Linkin Park, Three Day's Grace, (sometimes) Nickelback (thought not all the time so don't get mad because I personify it this way ;) ), and sometimes Green Day. Though most of these bands are described as Alternative/Metal. Once more, all about perception.
An example of moody person (another Emo form)-
Moody Kid: I want to kill myself now.
Moody Kid: I don't know, let's go play soccor! *Moody kid smiles*
1. Girls say they like "sensitive guys" (lie)
2. Guy finds out, so he listens to faggy emo music and dresses like a dork so chicks will see that he is sensitive and not afraid to express himself (lie). He dyes his hair black, wraps himself in a stupid looking scarf, develops an eating disorder, and rants about how "nobody understands".
3. Now an emo guy, he meets Emo chick and they start dating, talking about how their well-off suburban lifestyles are terrible and depressing (lie)
4. Emo guy is just too much of a pussy. His penis is too small, he's too depressed to bathe, and has more mood swings than emo chick, and he doesn't even have a menstrual cycle. Emo chick dumps him, saying "It's not you, it's me." (lie) as she drives off with Wayne, the school jock and captain of the football team.
5. Emo guy goes home and cries, proceeds to write a weak song and strum a single string on his acoustic guitar. Another emo chick sees how he is so in touch with his feelings, and the cycle continues.
This is the sad truth of the emo lifestyle/music, and now that I look at how pathetic it really is, maybe the emos DO have something to cry about!
boyfriend: I'm too sad to have sex.
girlfriend: I'm sad too; lets have sex and cry.
boyfriend: I'm already crying.
XxSlavetoAnguishxX: omg my gf just left me
acidburnedsoul: that sux man
XxSlavetoAnguishxX: i blame myself only i'm such an ass *cries*
acidburnedsoul: dude come over to my house and we can cut ourselves together
XxSlavetoAnguishxX: okay *cries*
acidburnedsoul: omg dashboard confessional has a new cd, i preordered it already
XxSlavetoAnguishxX: dude they're my favorite band to self-mutilate to
acidburnedsoul: i prefer to cut myself while watching Napoleon Dynamite on my bigscreen
XxSlavetoAnguishxX: dude that movie is so deep. i cry every time i see it
acidburnedsoul: me too. i hate myself
XxSlavetoAnguishxX: yeah we're such tortured souls, nobody understands how hard life is for us
acidburnedsoul: yeah we got it tough dude. pass the tissues
I just thought I'd clear that up after all of these "definitions" in which I have encountered an unbelievable amount of people who try to pass off their blatantly false pretenses as fact, and are slowly infecting others with their high-horse, holier-than-thou bullshit. Because honestly, with your ridiculous definitions, Beethoven, George Gershwin, and Britney Spears are/was "emo bands."
Now, onto the real definition.
In the early 90s there was a movement in the hardcore genre that came to be known as "Emotive Hardcore," spearheaded by Rites Of Spring. Harder-core-than-thou kids, who swore by Dischord Records a la Minor Threat, actually coined the term "Emo" as something of a put-down for the kids who really liked Rites Of Spring, Indian Summer and this new wave of "Emotive" Hardcore bands. That's right, "Emo" was once not something kids called themselves. The field exploded outwards from there - Level-Plane Records has always been the most famous Emo label. Acts like Yaphet Kotto, I Hate Myself, Saetia, Hot Cross, A Day In Black And White, Funeral Diner, I Would Set Myself On Fire For You, You And I, and hosts of others came in the next decade. Most emo bands have since broken up, but there's still the occasional hold-out (again, the majority of Level-Plane Records' roster has been a procession of emo acts). Like most DIY hardcore/punk of the time, a majority found its way onto vinyl and not much else. Some people consider bands like Fugazi, and later Sunny Day Real Estate, a progression of emo, but personally, I don't quite follow that philosophy.
Often, more recently, this gets intertwined with post-hardcore, and understandably so - that's nothing to make an issue of, since well shit, at least it's close.
Since the late 90s, though, bands have been emerging in the vein of Taking Back Sunday, Dashboard Confessional, and the thousands of their clones. As far as I can tell, some lazy journalist somewhere, writing an article about them, decided "Well, fuck, no one knows what emo is anyways, so I'll call these bands "emo" - sounds more appealing than bubblegum pop rock..." and the spiral continued downwards into the current amalgomation of bands MTV has told everyone is "emo."
Somehow, people decided that "emo" meant "emotional," which is obviously bullshit, as 99% of bands make music to illicit emotion, which would make "emotional" a completely all-encompassing genre from classical to opera to pop to rap.
Hope that helps.
Rites of Spring is emo.