So you really were in a lose-lose situation. But your response was solid; certainly better than the original case.

I thought it largely ignored the points and positions Wright made, and the counter-arguments weren't great. (I like Bostrom, but when someone makes a laughable claim like materialism is associated with no great philosophers, that's not a good time to bring him up; that's a time to invoke Hume, the Atomists and Stoics, Dennett, etc.)

If one is going to respond at all (and given how intemperate his response was, I would personally feel no obligation to reply), one should try to do at least a decent job which doesn't demonstrate one's opponent's claim that materialists don't know "enough philosophy to argue with a freshman" and possibly fostering a back-fire effect. (Hopefully wittily, like quoting some of Wright's bile and then sardonicly noting that Wright's religious conversion after a heart attack is itself an excellent example of materialism.) Strawmen are common enough without becoming a living one.