From the same site as the previous post, on the fake loading indicator of Gmail.
This is a bit of a pet peeve of mine – many sites are following the trend of using fake CSS-animated progress bars that give the illusion of progress instead of bothering to calculate it properly. The same goes for Github, Youtube and many others.
One source I seem to be able to link with this phenomenon is the good old Turbolinks, whose progress bar by default just does whatever in case progress isn't computable. (It does make an attempt though, as far as an attempt can be made, and to be fair, there are cases when it cannot.)
But on the other hand computing progress is hard, as can be attested by most anyone who's used Windows XP.
So it's hard to come to an agreement on this. Giving a false sense of progress might be good UX, but also confusing to the pedantic; showing indefinite spinners might be more technically accurate but also more boring.