The term "nimbytard" is a more offensive version of the more common nimby.
A nimby is a common type of person who thinks of themselves over the greater good (not in my back yard), this derivative includes tard based on Latin for slow or delayed. Thus nimbytard implies the nimby condition is particularly severe, and in some way a medical condition affecting the brain.
If one is nimbytarded they possess the traits of being selfish and slow, and often cause delay or obstruction to projects that would otherwise benefit the greater good.
A: Ewww nuclear waste... let's leave that in China, we don't need near our homes here in Australia.
B: But our nation and this continent are the most stable in the world. We are a perfect place for nuclear waste storage. Plus it could be a good revenue stream, and a social conscious and responsible thing, for the greater international community.
A: I don't want it near me! Excuses and things! Would YOU want to live near it? No way!
Alex B: You sir are a nimbytard. You need to get that shit checked out.