That is abroad sweeping assumption and I admit no such thing, other than you are guilty of assuming.
There were various options available to me when people lied. If they were already charged with something, and lied to me, I documented it and filed the paperwork with the case. Some situations resulted in an arrest for lying when there was no charge or pending charge. Sometimes I just laughed and ignored it.
It's unfortunate that there are cops who lie on the stand. When I lost cases, it made me a better investigator, and lying was never an option to win a case.
But since you are so jaded about the whole justice system, how would you change it to make it acceptable to you?
I'll have to ponder on that. It's a great question and deserves more than my typically flippant response. I'd like to see LEOs accorded the same treatment as any other witness, for starters. Get caught lying on the stand, go to jail. But I'll agree on one thing, I'm jaded. Look at this moment: I'm arguing with a detective over the meaning of the word, "lie."
I'm not going to get into a discussion of the utility of the stretching of truth to get a suspect to break, but rather the freaking out when the suspect also stretches the truth on the other side of the table. You can't get charged with a crime for "bluffing," as you put it, but the guy you're questioning can, and as you point out, is often charged and jailed even if there was no other crime. No wonder you laughed. Do you see any problem with that?
When you do it, it's "bluffing." When the suspect does it, it's "Obstruction of Justice." There's another word for that, "hypocritical."