Why do people look down on people who have thought or think about suicide?

I have been diagnosed as depressed, bi-polar, etc. I think about death and ways to die all of the time. I have tried suicide hotlines, but I am never going to call one ever again. The woman I talked to was rude and I felt like killing myself even more while I was talking to her. Sometimes I wonder if suicide in my religion (christianity) is as bad as people make it seem. They make it seem like I’m going to burn in hell if I do it. I mean if God is understanding..then he would understand why I did it, right? I just wonder why people make you feel like such a horrible person if you talk about it. Is it because no one wants to hear it or what? I’m confused.