If Christians are sinful (some will even say they are evil at heart), then why listen to them?
Isn't listening to people who say they are sinful (ie. imperfect, fallible, evil even) completely stupid?!
Because the born-agains are telling you the truth. They are doing God's work. They are following His orders to be fishers of men. They are trying to save your soul despite your objections. Most of them have been where you are. They don't ever want to go back.
You listen to teachers, bosses, "experts", scientists etc and they're not perfect. No one is perfect except Him.