Complaining about proper punctuation in web page titles seems a little pedantic. Using colons and other strange "punctuation" is a substitute for graphics and styling since these are not available in title bars. For those cases where it is meant to be sort-of punctuation, I'd say titles on the internet simply follow a different set of rules and conventions than prose, or anything else prior, because they serve a diff…
The New Yorker (e.g.) is a publication known for its typographical pedantry, for example writing diaereses in words such as coöperate or naïve; it’s entirely uncharacteristic of them to have sloppily punctuated titles.
Regardless, I'm guessing the editor of the New Yorker has been to their website. Her approval defines what it is that the New Yorker does, and what it is known for. Sniping at such an organization previously known for pedantry is a bit presumptuous.