Why don't conservatives realize that pulling the plug on a human vegetable isn't wrong neither is abortion?

You are not right. You are not wrong. You have an opinion. Live by it and apply it to your own life and choices. However strongly you hold that opinion however does not give you any special rights to tell other people what or how to think. You are free to judge people based on whether or not they believe what you believe, but it won't get you anywhere.