> their daily duties and training revolve almost exclusively around policing mainly civilians, citizens of the same country.
That is the part that is not universally true. There are plenty of Gendarmeries who are soldiers first, with combat training and ethos, who also perform policing duties, the Marechaussee included.
Fair enough, but Wikipedia confirms that they all have civilian law enforcement and police duties so clearly their training, tactics, and experience revolve heavily around dealing with civilians.
I'll still take that over "soldiers only", even more with US's very active military where the soldiers routinely see active combat. Both the theory and practice shapes their "soldier vs. enemy combatant" world view. That's a hammer if I've ever seen one.
That is the part that is not universally true. There are plenty of Gendarmeries who are soldiers first, with combat training and ethos, who also perform policing duties, the Marechaussee included.