It's not so much his opposition to portability that bothers me personally, which I personally disagree with and think that it should be strived for to a reasonable degree.

Rather, it's his patently false and almost obnoxiously smug view of the BSDs as these slow-moving operating systems that simply follow Linux's trail, and his deeper implications of forking being negative and that Linux should play a game of catching up against OS X and Windows instead of doing its own thing.

Then his reasoning against portability seems self-defeating. He says that "i need to reach customers using windows" is a good reason, in which case you can substitute "windows" with any OS and have a purportedly valid reason for portability.

Not living in an arrogant monoculture that seriously believes you're leading the pack and everyone else is biting your dust sounds like another good reason.