Because YOU killed someone, and worst of all you killed yourself. How can it not be a sin? In the bible, it says not to make other Gods, basically not to taint God to fulfill your own satisfaction. Unless that person can ask for forgiveness, then they going to Hell because yes, that is a very bad sin. If I was to kill someone, would I go to Hell? Heck yes! How...how can you not see it as a sin?? I'm so confused, it's so bad that's like saying Ted Bundy was an angel. In Christianity, as I am a Baptist, I quote this, "Suicide is certainly a sin—because it robs a person of the sanctity of life and the full time given to them by God alone. Family and friends of a believer who has committed suicide should never worry about whether their loved one is in heaven."
It's not an unforgivable sin as it is shown in (Jhon 5:24; 10:28) But, they must be saved and never lose their salvation. For a Christian, it's a horrible sin because it's a life wasted that God intended to have a purpose for. It's a blatant argument to say it is not such as a sin because it is murder and we do not condemn it. I don't know about you, but they going to heck. One more thing, what if you killed someone? Hung them, slit their throat, aborted them, starved them? In the 10 commandments, it says shall not murder (particularly one another); And someone not committing sins? Well, too bad because they just broke that perfect record by killing someone. This body, see it? It the mirror? This body God gave you? Yeah, that life God gave you? The only person who can end your life is God: no one decides to end of life but God. To me, that is why murder is the worst, and abortion. It's murder. It's killing yourself. Killing yourself. Let me say that again, IT'S KILLING YOURSELF!!!
Might I add something else about your statement, someone who is a "good person." Your most likely not a good person, I know I'm not a good person. Why? because in the old Testament [before Jesus], you must ask yourself, have I ever stole, looked at a person with lust, told lies? I've stolen, I'm sure you've stolen something once. I've sure lied and I've looked at a person in lust and yes, I'm 12. So, am I going to Heaven or Hell if I die right now? Hell. I'm going to hell. But, because Jesus died for my sins, I will go to heaven and be admitted to my father. When I say this, God is judgemental, he would look at me as a lying, adultery thief. But, as this part to me is confusing, if I place my faith in Jesus and what he has died for then I will be in Heaven. Now lust, lying, thievery, it's only human. I'm only human, you are only human. But this sin, this the devil.