That article might have been more useful if it came from the other (the non-consensual) angle, i.e. showing that while beating a child is considered bad it is treated no where nearly the same as sexual assault. From that one could show that the sexual component triggers some potentially irrational reaction. Then one could argue that sexual non-consensual acts should be treated the same as non-sexual non-consensual. And finally after establishing that one could actually generalize that to consensual acts.

Of course with children one would need to define 'consensual' since the problem with pedophilia is that children are thought of as unable to consent.