We have spent years calibrating how we handle titles and it's one of the most consistent things we do. I know it can be nonintuitive to casual readers at times, but that's because applying that guideline is surprisingly complicated in practice. If it were your job, you'd soon find that as well. Also, people only notice the cases that stand out, which tend to be the edits they dislike and feel we got wrong (which maybe we did). That's a sample bias. Probably less than 5% of title edits even get noticed. Maybe even less than 1%.
We're always happy to answer questions about it, as well as to change titles in response to user feedback, which we do regularly: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que....