The incident was handled well by crew and ground services, best we can tell. It's a terrible loss of time and money to respond to these kinds of things. But in current conditions, when someone says the magic words, it has to be taken seriously.
Just because someone looks mentally unbalanced, it doesn't mean he hasn't also done what he says he has done. Having to divert just to get a crazy off the plane could be seen as getting off easy.
As much or more than the folks in the cockpit, these deals are the times when the cabin crew more than earns its pay. Talk about psychological pressure...