*edit: I found the answer
I thought it was a dumb feature because it is actually a standard in 2d and 3d rendering. Not using it is a real waste of performance and if you are learning opengl, it is one of the first things you learn. I don't about how blender was actually programed so it may be a lot more complicated than I'm making it out to be but I'm pretty sure it was optional because they were messing with the rendering engine, which is a dangerous thing to mess with this late in development because it can easily break the application, and they where afraid it might cause some trouble. Now they seem confident enough to remove it as a option.
Edit: Now I noticed I'm answering it a year later but I'm ok with it.
