The term "extremism" defines exactly nothing. It is a term used to connote an issue no one dare denote. It is a term used by devotees of the cult of moral greyness to 'define' that which they fear the most--principled adherence to truth, morality, and ethics. It is a term used by political moderates to discredit constitutionalists who believe in unalienable individual rights exercised in rational self-interest, the liberty to exercise those rights, and capitalism, which makes possible the acquisition of property--the source of all unalienable rights.
Funk and Wagnalls New Practical Standard Dictionary (1947) defines the word extreme thus: "Ex-treme adj. 1. Being of the highest degree, at best, worst, greatest, etc...." Extreme, then, is a measure of degree. When the word "extreme" is used by political and media smear artists, it is intended to mean an extreme of any degree regardless of its nature. This implication is inherently evil. It means that extreme morality and immorality are equally undesirable; extreme honesty and dishonesty are equally immoral, and extreme virtue and extreme depravity are equally evil.
Defining oneself as a moderate is an admission of being a compromiser and an appeaser. Philosophically, what, then, is the implication of compromise between the truth and a lie? What is the implication of compromise between morality and immorality? What is the ethical implication of compromise between principled action and unprincipled action? The implications are advocacy of lies, immorality, and unprincipled action.
Politically, what is the implication of compromise between unalienable individual rights and collectivism? What is the implication of compromise between liberty and slavery? What is the implication of compromise between capitalism and socialism? The answer is, the same result as the compromise between food and poison--death: the death of unalienable individual rights, the death of liberty, and the death of property. The implications are the advocacy of collectivism, slavery, and socialism.
The term "extremism" is nothing other than a smear; a smear used by self-proclaimed moderates, who have no principles, to defile those who adhere to principled thought and action. It is a terror phrase intended to instill a sense of guilt and uncertainty in the irrational mob by reference to undefined and constantly fluctuating ideological package-deals.