In order of increasing severity or moonbatiness:
1) A person who adamantly holds a particular opinion for no other reason than that's what their organization, friends or family members believe.
2) A person who makes up facts and data to support their argument because they are unwilling to consider that they may be wrong.
3) A person who gives very vague unverifiable references to scientific or authoritative sources to browbeat people of opposite views into submission. (Generally because they are arguing points that they cannot support with verifiable data. See #2)
4) People who support causes that have no verifiable benefit and in fact may cause more unintended damage or harm than the original problem.
1) Both Muslim and Christian crusaders could be considered moonbats.
2) Partisan politician that fights for their Party regardless of what is best for the country or their constituents.
3) Both sides of the global warming argument have their moonbats.
4)Activists who fight to shut down a nuclear power plant which then must be replaced by four coal or oil burning power plants that produce acid rain and green house gases are definitely moonbats.