Because you're given two choices and you've taken the easy way out. Coward shyt.
You can deal with whatever it is that you're suicidal over, fix the problem, fight through it, wait it out even until it gets better. Or you can just quit.
An argument can be made that it takes courage to commit suicide. "Fight or Flight" is a common term ascribed to the natural response of both humans and animals when confronted with a life threatening situation. In other words, our natural makeup will cause us to do whatever it takes to preserve our life. Whether that means resorting to physical defense, or to flee from whatever situation it is that we're dealing with.
That said, 90% of the people on this board, and anywhere else if handed a loaded gun, would be too cowardly to put that thing to their head and pull that trigger. Myself personally, I'm scared of heights, haven't been on an airplane in years and have no intention on boarding one anytime soon. That said, for someone to jump off of a building from a significant height, a height so high that death is guaranteed, that person is anything but a coward from my perspective. I agree with the breh above said though, mental illness is the culprit behind most suicides and this society for whatever reason doesn't address it properly either due to apathy or lack of resources.
At any rate, why be a dikk towards the living by sh!tting on their loved ones who took their own lives? You posting that bullsh!t isn't looked upon like a form of tough love in any way. You just look like a callous dikkhead.