Luckily our cops are only half bad (one quarter bad apples, one half who doesn't give a fuck and just can't be bothered to do anything, one quarter trying to fly under the radar and bootlickers, one quarter decent) in my country and nowhere near the levels the US have to experience. I have to work with them due to working in EMS and there have been dozens of situations I was happy for police backup - more than situations where I wish the cops weren't there.
BUT: I am also a white cis male and the experience is very different when I am not working - and verrrryyy different when I was still obviously a leftist than it is now. (Still am, but bidding it better). They were plain right obnoxious then and I would only call them for a situation I knew they either be pissed off enough by my opposite automatically or I know I can make them do what I want/need as I usuall know the relevant laws and their procedures well enough to pressure them. So for a perp with a knife? Yeah, definitely. For a burglary? Yes because I know how to make them do their job if the half who doesn't want to do it arrives.
There are dozens of photos that most of the military unit who were active at the parliament did not have magazines in their guns and often had blue training guns in their holsters or blue training pins in their assault rifles.
This is nothing you do by accident - especially not in a highly qualified military like the SK military. It is a very good way of making sure that for starters none does something stupid like kill a MP, but also to show other units (and people) that you are not really on the side of whoever commanded you to do what you do. And it mak sure you look favorable in court if things turn against you.
Considering that this was not a singular occurrence but happened amongst all types of units someone has ordered them/coordinatated this.
How high up that was? Who knows. But it was a pretty strong sign, especially towards other units.
Who knows, in theory it could also be a valid scenario that the military was "faking support" to motivate Yoon,knowing that he will be impeached after that.