I have no particular need to apply the label of "sexist" to this guy. I have no opinion, nor enough information, to say whether he should be fired or not.
I do think he's profoundly wrong though, and think his arguments about biological differences bear at least a passing resemblance to some wholly discredited arguments.
>> avoiding the content of the article itself.
That's what I'm talking about. I also think his ideas wouldn't be terribly effective, but I think villifying and dismissing him just for saying it does more harm than him saying it. That's why there are people focusing on the reaction. It doesn't really matter who the onus is on to justify his claims if you're not going to actually listen to anyone who disagrees with you anyway. And you can't claim you actually listened, because you explicitly said he was arguing in favor of excluding people based on class. That's what you heard from all of his suggestions to approach inclusion a different way.
edit: I'm going to give a personal example: I strongly supported legalizing gay marriage, but I also support the right of anyone to refuse to bake a gay wedding cake or to run a church and not perform gay marriages. And I've had numerous former friends chew me out and shun me for being "intolerant". It's that attitude that makes reasonable political discussions harder and harder (at least in the US right now) because it makes everyone fear to give up anything to reach a compromise or to even understand each other.