OK, Monks have some very special traits.

They get 4 skill points per level and have
Sense Motive, Listen, an Spot, Wisdom based skills.
They have Concentration, a Con based skill.

They get Wisdom and Dex to AC, plus they are good at unarmed combat.
They get improved Grapple as a bonus feat, if they want it.

So they are intended to be good at observing thing.
They have concentration so they won't get distracted.

They have good saves, and become immune to natural disease and poison.

This can only mean they are intended to spend long periods of time observing in an area that in not very sanitary. They need to be good at fighting where there are no weapons or armor, and they need to be good at grappling, something that is only useful when you already have overwhelming force on your side AND you need to restrain your target without hurting them.

They also are in a class that penalizes you for leaving it, unless to specialize.

At the height of their profession, they are no longer considered human.

Monks are prison guards.