I agree. and I'm surprised they made a blog post about this. The details of this seems more embarrassing than it is enlightening.

>Comment bundles are particularly heavy: They contain the comment text itself as well as its id, timestamp, and author metadata (including profile picture). ... Generating profile picture URLs is a CPU-inefficient operation because we must dynamically compute the correct CDN URL. The more comments we load, the more profile picture URLs we need to generate.

Is it loading the entire profile picture with each comment? Not just a small thumbnail?