It is easier to cache stuff for users who are not logged in as it is the same for everyone. and everyone is looking up on Hackernews at the moment to see what is wrong with slack, which is probably the cause of the slowness.
The point count for most articles is consistently lower on a view of the non-logged-in homepage. I assume that means they are cached more aggressively for non-logged-in. There's also the username and karma count in the top-right.
