Why would people choose an extremist form of government(either ultraliberal or ultraconservative)to rule over them?

Look for this book in your school or local library. Excellent explanations

Political Extremism and Rationality
Edited by Albert Breton
University of Toronto
Gianluigi Galeotti
Consiglio Nazionale delle Ricerche (CNR), Rome
Pierre Salmon
Université de Bourgogne, France
Ronald Wintrobe