As pointed out, he's pretty important guy in linguistics, and at least one of his theorems there is important in the theory of computing too.
When it comes to politics, I find it delightful how he really tries to argument rationally, I don't remember a single ad hominem from him, and how he tries to think things rationally rather than emptionally.
However, he's to confident with his views to my taste. I often get a feeling that he doesn't really acknowledge things possibly being more complicated than he'd like to think. His books are well sourced, but often I wonder, whether he's been picking things that just fits his views, and whether the sources are as very good.
Those are minot issues though, I like his thoughts, but don't think them as authoritative.
And his opinion on porn is of course wrong. There's a lot of good porn that isn't about female humiliation too. I'd add references, but that would earn me an infraction.