[sciurus]

Context clues.

If I was in a sportsbar and heard someone dissing the NFL, I wouldn't think "What do they have against the National Forensics League?"

On HN, if you see an acronym where it doesn't make sense to you, great! Most likely you're being presented the opportunity to learn about some cool technology.

[alttag]

I did (learn something), but not knowing what "Py" was, there were no other context clues in the headline. HN is friendly to researchers too, so the setting is appropriate for the other interpretation of the acronym (and makes the football analogy mildly condescending).

[lobo_tuerto]

But accurate.