I'm just guessing, but maybe it was selfie/portrait accidents in the past, where people came to close to the exhibits, toppling them over.
After taking a better look: everything seems firmly secured here. I still think preventing portraits is a possible explanation: No accidental touching of the objects when people hold their face too close, or grabbing of objects when they stumble during posing.
A lot of museums ban photography. I like to think it is in part because it is annoying to everyone else. Though also it can help sales of prints at the gift store.
That place is great! Much better than what they used to have back in the day. I was rather impressed when I visited a few years ago not knowing this had been built since my last visit.