I'm sorry, but that is a really rude and insensitive comment in my honest opinion..
I'm sorry that bikers might add a little more time to your daily commutes, but that biker is also a living human being that has family, loved ones in their life. Making comments about hitting them while your driving a large vehicle with no qualms is very tasteless. Hitting a biker with a large vehicle can cause serious injuries and death. There was a woman in a town near me on a bike ride in town with her daughter just recently that was hit by a car and sadly ended up dying from the collision.
Also, your comment seems to display that you have some signs of road rage which is very dangerous for yourself and others. Everyone in this life can make mistakes, as we are human. I don't think that makes it right to purposely commit vehicular assault on a pedestrian with no protection whatsoever. I know I've made some mistakes when driving/running/biking, and I would appreciate it if someone would purposely not hit me with their car, just as I would likewise do the same for any other person driving/biking/running.
As hard as it is sometimes, I feel that we should treat others with decent human courtesy and respect, despite their mistakes/faults, as I likewise have my own.