I think he also specifically defended Minsky, IIRC, onn the grounds that it wasn't clear Minsky had any reason to suspect that it wasn't voluntary and that, given that, did nothing morally wrong (if you think sex with prepubescent children can be voluntary and if so not harmful, obviously it's unsurprising to think the same thing for post-pubescent near-adults); his defense of Minsky is still controversial (people don't generally think that the age of consent is a bad idea, especially when there is a also a wide gulf in ages between parties), but not as extreme as his separate defense of pedophilic sex generally.
I did not know of this Dutch group, and I think their purpose is wrong.