A letter asks Republican vice presidential nominee Paul Ryan and others to decline an invitation to speak at the event hosted by the antigay Family Research Council.
The comparison prompted a response from Log Cabin and some distancing remarks from LGBT leaders.
The country singer made the comment during a Texas concert in which he also made fun of 'queer guitar pickers.'
California lawmakers officially passed a bill to ban sexual orientation conversion therapy on minors, with Gov. Jerry Brown expected to sign the legislation.