I'm sure it's horrible and humiliating, but a) it's not torture (a word another commenter used), and b) you're admitting known-unstable people into very close quarters with doctors and nurses who will care, feed, and bathe them over the next several days/weeks.
So, yes, hospitals have decided this safety check is warranted. "OMG covering their ass!". Yes, exactly. They're probably covering their ass because sometime ago, someone did get something in, and bad things happened.
If I were a doctor/nurse working in a psych ward year around, I would appreciate the safety check.
The author says, sarcastically, "I was here for my own good" (with various dangerous items removed). She was actually right. They take precautions for a reason, not just to be assholes.