An "unabashed supporter" is someone who openly and proudly supports a person, idea, or cause without feeling embarrassed or ashamed about it. Full definition
To be sure, Barth has a number of unabashed supporters who find themselves fundamentally in phase with his basic enterprise. (religion-online.org)
He may despise de Blasio but Republican City Council Member, and 2017 mayoral candidate, Eric Ulrich is an unabashed supporter of a long term extension of mayoral control of the school system. (newyorktrue.com)