I'd forgotten JM was that guy. There's some discussion going on over at bigtitch's journal about that blogpost; he seems not to have expected quite that level of backlash, and in general the consensus is that he probably ought to have at least laid in a supply of flame-proof undies in preparation. Some of the remarks were clearly out of order, but he got quite a bit of praise and support in between. Perhaps he's unused to fandom?