Medical science is, alas, still a bit of an oxymoron. The nice thing about this case (as is explained quite well in the article) is that it is unusually well-documented, so it gives the scientists a bit more to work with than is usual. The conclusions we can draw from it are:
1. PrEP is not perfect. Very good, yes (and the continued collection of statistics bears this out). But not perfect.
2. In cases where compliance is good, factors other than viral resistance are very likely to play a role in transmission in cases of PrEP failure. In this particular case, bacterial infections and low blood levels of Tenofovir (likely due to increased clearance) are probable contributors.
I'd like to add my personal opinion that the doomsaying and descriptions of gays as doomed, flawed, or defective, which showed up in a number of posts in this thread, are really not very constructive. I hope that those of you who feel that way can get through such feelings to a more positive view of yourselves and of us as a collective. Life is a terminal condition, and the fact that transmissible disease (far from limited to HIV) is a relatively rare cause of it, is an anomaly of the last century.
And let's not forget that it truly has gotten better. My ex-BF, whom I convinced to go bareback in 2000 or so, seroconverted sometime in the early 2000s. He died a couple of days ago of complications from heart surgery, without having suffered notable ill health from HIV.