like fantasy being a closed genre - maybe I'm reading the wrong stuff?

I don't know what objective data you expect him or me to point to, but I agree with him on this one. Fantasy is, by and large, hidden authoritarianism and other 'closed' social structures; from the overt medievalisms and Great Chains of Being to the hereditary succession of power to the straight fascist allegories. Not that SF is perfect either, but it tends to be much better and more challenging, especially towards the harder end of things - I don't know any equivalent classification for fantasy.