Because he questioned taxes and the weekend crowd thinks that's heretical and won't even entertain the discussion of why things are that way let alone whether they're good or bad.
I had just the sort of discussion you're talking about on that big thread about PG's "how to make a billion dollars article," where for some reason people couldn't even fathom that there was even a way to tell whether certain taxes are good or bad, and couldn't understand the logic of doing so.
https://news.ycombinator.com/item?id=48526360#48527840