It's not an especially crap comment, it's just a joke you didn't get. Jokes don't do well here admittedly.
The jokes thing is a tricky one for HN. I love comedy and I love wit. I'm sure most of us do. But when you're optimizing for signal/noise ratio, as HN tries to, there are tradeoffs. On the whole, I think the community habit of downvoting most (not all) jokes is reasonable for what HN is trying to be.