I'm also extremely skeptical of the NV police but I've heard stories from opinionated people at both extremes and many in the middle and I've settled somewhere in the center. I think both sides deserve a generous heaping of blame but it's up to BM org to make sure that the festival goers don't have to feel the fallout. They haven't done a great job of that. Here's where it gets complicated because there are several levels of law enforcement involved with decades of history with the event. Black Rock desert is also a hodge-podge of federal and local jurisdictions so it pretty much guaranteed a mess.
From what I understand, Burning Man was a curiosity in the 90s that the NV LEOs were largely ambivalent about but the relationship started to sour in the early 2000s when BM started really growing year after year. The county police did start to pull some sleazy power moves, I'm told due to an overzealous/tee-totaling Washoe county sheriff, but the BM org response was naive at best and absolutely childish at worst. The event was straining the police departments and other services in ways neither side had never imagined so I don't know if the police were power tripping or if they did genuinely need more capital to carry out their duty. Instead of capitulating to some demands and compromising like any other large scale event has to, BM org tried to get everything they wanted and in the process acted like "a bunch of big city Californians who think they're better than small town hicks" (I talked to a county LEO about this after a domestic violence arrest at an adjacent camp and those were his exact words). Mid-2000s is when I believe the relationship became antagonistic and after that there was pressure from law enforcement and the BLM to bring in more feds in greater numbers. Luckily, BLM and LEOs didn't try to use the atom bomb and block the event entirely but behind the scenes there was a year long struggle to get the event up and running on time.
After a while (late 2000s/early 2010s) BLM decided that the event had grown too big and put on another layer of bureaucracy that BM org had no experience dealing with, which again strained the relationship. Meanwhile, something happened that angered the feds (who were only there to show the public they weren't ignoring a oasis of drugs in the desert) and they started involving themselves with BLM's negotiations which further weakened and emboldened BM org. I don't know what really happened in the early 2010s but it all culminated in the 2012-13 lawsuit which cost the county millions and left a sour taste in everyone's mouth. After that LEOs went crazy with enforcement and tried to recoup their losses, which meant that all the nastiness behind the scenes started to spill over into the main event.
I've built up this perspective second and third hand over the years so take it all with a grain of salt. At the end of the day attendance and ticket prices skyrocketed, law enforcement became more and more obstructive, and the quality of the infrastructure didn't really improve but its hard to know what's going on unless you're in the org.