If the accusation of bigotry were accurate, it would be a reasonable and, possibly, effective defense. Since, in this case, it is untrue, it is only a personal attack masquerading as a legitimate defense.
The best defense against a personal attack is to either ignore it and let it be seen for what it is or respond calmly with an empirical argument.
In this case, it strikes me that the accuser knows the accusation is unfounded but, with no way of winning the argument legitimately, the accuser is trying to destroy the debate itself by reducing it to a name calling contest (which is a victory of sorts).
Cooler heads prevail. LOL
Or puts words into peoples mouths and conducts straw man arguments that do not address the real concerns or issues at hand.
I too have come to the conclusion that some peoples real motivation is to provoke and seek conflict by using the name calling tactics of the left instead of replying with more reasoned and well thought out responses.