Behind the stage seats aren't a new thing, Pearl Jam have done it, Stones, Paul, Metallica, Arcade Fire, Springsteen, Fleetwood, Elton John has done it, the likes of Prince and David Bowie too.. it isn't limited to just one artist.
The idea of a musican / band filling a stadium, arena or venue with as many fans as they possibly can is not limited to Taylor Swift. It's 100% find that you don't enjoy her music / aren't a fan of her. They are sold as a restricted view, and when the tickets went on sale - that was very clear when you were selecting where to sit.
And she isn't alone in expensive tickets. The Rolling Stones’ 50 & Counting tour some tickets went for £950. Elton's farewell tour had people spending a minimum of $150 for the seats at the back. Led Zeps reunion in London was around £250 a ticket... Like I say, 100% fine that you dislike her but I think your thought process might be misguided.