I'm sure he can defend himself, but Ben never said he agreed with that line of reasoning. He's just laying out the argument that Bennett was aluding to. The whole issue, without getting into the specifics that keep derailing this, is: Statistics sometimes point to facts that we wish weren't true. If we base policy decisions solely on a pragmatic analysis of these statistics, we end up doing things that are simply unacceptable.
Bennett used a clumsy analogy to try to make this point. The specific analogy may have had some racist assumptions built in. It also controlled for the wrong factor, rendering the analogy invalid in any case. And it was in service of discriditing a policy that the majority of the population supports.
For his argument to work, he would first have to convince that majority that their position was as morally unacceptable than the straw man he set up. His whole chain or reasoning has more assumptions than the rapture.