It was a response to a question. The LP is about same sex / any sex marriage. Under the LP, there would be no laws restricting a father from marrying his son.
Sure, if you read enough into it, it could be what you claim, but you're an extremist.
Reading far enough into Republican Party platforms and adopting an extremist view would reach the conclusion that the Republican Party favors FBI/DEA/BATF stormtrooper killing squads that execute drug users/dealers on the spot with no right to trial by jury. OH! They are already doing that. Do you have your pom-poms out?