And if only developers understood UX.

The "lie" the author was complaining about was that Firefox is miscommunicating what it did: It warned that a concrete file was containing malware when it actually found a suspicious domain.

Depending on context, that might make a huge difference - e.g., if a user got such a warning for a file they uploaded themselves, they might get the wrong impression that their system is compromised.

As the author noted, simply describing the actual threat would clear this up.

> Sure, there are some costs to false positives, but they are dwarfed by the cost of false negatives.

This strategy has blown up a number of times already. If you present too many false positives, users might lose trust in you and ignore your predictions altogether.