Misbehaving crawlers are a huge problem but bloggers are among the least affected by them. Something like a wiki or a forum is a better example, as they're in a category of websites where each page visit is almost unavoidably rendered on the fly using multiple expensive SQL queries due to the rapidly mutating nature of their datasets.
Git forges, like the one TFA is discussing, are also fairly expensive, especially as crawlers traverse historical states. When the crawler is poorly implemented they'll get stuck doing this basically forever. Detecting and dealing with git hosts is an absolute must for any web crawler due to this.