Discounting an argument because of the person making it is pretty much the textbook definition of ad hominem fallacy.

Also, it should go without saying that being a theist doesn't automatically mean one believes in a loving and all-powerful god watching over us. And anyway, I still don't follow the logic that being a theist means one can't make sensible decisions about the Singularity (insofar as one can say there are "sensible decisions" to be made about something that's basically a sci-fi construct at this point.)