what's the deal with parents backing up their ill-behaved snowflake kids?

Sounds like a personal issue rather than a programmatic one. Every PTA/PAC/Magnet event I've attended the administration has been very supportive of both the magnet and diploma program. My DC doesn't have any issues with teachers or staff (although there have been one or two instances where I've had my doubts, but DC said no issue, therefore, no issue). If your daughter was being disruptive during an assembly I'm not sure what you expect other than whoever was running the assembly to ask the whole group to pay attention and stop talking.

How is she enjoying the academics?

My daughter is in the magnet program and has had a terrible experience with the new IB staff so much so that I would never recommend the magnet to incoming 8th graders. However, that may be what the school administration wants as they almost seem anti-magnet. On another note, the IB staff has been heard makng some very deragatory comments. For starters students were called elitists last year by the IB Coordinator. Yesterday when a few juniors in an assembly on gun control were not listening the entire group of juniors were told if they did not take the assembly seriously they would be a Parkland. The magnet used to be such an amazing and professionally managed program, but I do not feel it still is.