That's because in the future all robots are based on PETMAN, and thus serve the dual purposes of being humanoid killing machines and wearing clothing "to simulate how a soldier stresses protective clothing under realistic conditions."
The clothing of the future is very thoroughly tested.
Pure speculation, but given the amount of exposed machinery (I hope ribbon cables in 2202 are pretty durable) on the head and arms, some extra protection wouldn't be unreasonable.
Ironically, a lot of this stuff would be considered old-school now, much less in 188 years - non-integrated kneepads and drop-leg holsters dragging down a web belt, for example. (The rifle is also based on an Accuracy International AW-pattern rifle, largely unmodified from the thumbhole grip back, but the shape of the receiver and distinctive bolt handle are also visible.)