Actually, fundamentalists have had an answer for the arguments in that letter for a long time. The rules the letter mentions were all applicable under the previous "dispensation" of law. We are currently in the "dispensation" of grace. But Paul let us know that, unlike the rest of the instances cited, the status of homosexuality as an obomination hasn't changed.

The argument has no merit for me, because I see dispensationalism as a clobbered up body of interpretation that exists largely because literalist fundamentalists realize that they have serious problems without it.