The biggest plotholes in this movie

As described in this video beginning at the 5:34 mark:
https://www.youtube.com/watch?v=hMDu1n0FusA

*How is Jack Palance's bad guy character Perret able to manipulate so many people in illegal procedures?

This goes into the second point:
*If the system is so corrupt then how are Tango and Cash still able to do such a good job at police work?

*Was it really a good look for Tango and Cash to plead no contest? While it's not exactly the same as pleading guilty, doesn't it still ultimately make them look bad as characters? If they were simply found guilty then it would've made more perfect sense for them to be sent to a maximum security prison. Why did there have to be that plot point about Perret making them go there?