In the second place, the very term "homosexual agenda," is an expression of intolerance as well.
Tolerance for people who are minding their own business is one thing. Tolerance for people who are attempting to force "celebration" of homosexuality is another.
Horowitz's blinders nothwithstanding, there are groups of activists who are tireless in their attempts to portray homosexuality as "good", "normal", and something to be celebrated. Anybody who doesn't share that opinion is tagged with the idiotic epithet "homophobe" and labeled a "hater". Anybody who has religious or other misgivings about how "gay" a homosexual lifestyle is is demonized.
You don't have to be a "fundie" to believe that homosexuality is not good for the people who practice it.