Ask HN: Why does Keybase.io require karma 1?

Just created my hackernews account and went to prove my identity with Keybase.io and received this message:

> ATTENTION: HackerNews only publishes users to their API who have karma > 1.

Does anyone know why this is the case? I'm curious to how they see this proving into identity... Or is it purely an abuse mechanism?

People where posting their hashes as new submissions which is not an acceptable way.