I understand that MPs have a job to do, but as whole, the ones that want to become MPs usually have something up their butt that makes them want to automatically have superiority over other people. What that means is that they were pr!cks before they became MPs and usually only those kind of people want to become MPs.
That's usually the reason that many civilian law enforcement agencies don't want to hire ex-MPs.
As far as your Vietnam story, I call "Bullsh!t".
While deployed in Kosovo and doing joint ops with a Russian Airborne unit, we interdicted guerrillas trying to bypass a checkpoint we were doing with the Russians. We called back to the base where there was a detention center to let the MPs know that we had prisoners to be taken to the center and be questioned. Since this was the first time we had this situation, we were surprised when the MPs finally arrived four hours later and informed us that THEY weren't going to transport the prisoners, that they were only there to escort US taking the prisoners to the detention center.
So we had to call back to our base, wake up another Scout section (by this time it was night), have them get up, dressed, load up their vehicles, and come to our location to get the prisoners, and then take them to the detention center. By the time the other section was done, they had to come back and relieve us since it was their turn to do operations. That was just the beginning of our dislike for the MPs.
The only time we saw MPs were on patrol in the cities or towns. We never saw them on the borders where much of the fighting was taking place.
The only time we really saw MPs was when a busload of Serbs was hit by a IED and several Serbs were killed and wounded. All the Serbs towns and villages in the area erupted in riot, with them blocking major roads preventing movement by NATO forces. For days, the MPs were trying to deal with the situation, with our Recon platoon having to sit in Humvees in full riot gear just in case the MPs needed us. Finally after several days of the MPs not being able to handle a situation where a Serb town was blocking the route between the two big bases in Kosovo, our Task Force commander turned us loose on the rioters and we, NOT THE MPs, ended the riot.
And that's just two situations.
The person who said that MPs get in a lot of trouble for drug use, DUIs, etc was correct. Then there's situations where MPs fail to do their basic jobs, such as an incident where a person was trying to use a fake ID to get on post who was serched and then later killed themselves with a handgun that the MPs failed to find, while in custody.
I realize that there's a need for MPs/SPs, but they're not all that by any means.