Bigotry and racism, or another other kind of systematic discrimination, are related, but not equal. Almost all bigots must, at least on an implicit level, believe in systematic discrimination, or at least their own right to discriminate. However the reverse is not true: an individual can systematically discriminate, without feeling any bigotry themselves, or make use of the bigotry of others for political ends.
A defense against the charge of bigotry does not prove the person in question is not a racist – or holder of equivalent ideologies e.g. sexism. Nor does it prove that the person was not a mere opportunist, pandering to the worst instincts in others.