“but man they violated all kinds of laws to get a bad guy”
Before the 1960s, there were fewer laws regarding the arrest, conviction, and imprisonment of criminals. For example, there was a time when the police didn’t have to inform a suspect of their rights. That changed with the Miranda decision in 1966. The Supreme Court did immense damage to the country in those days with its rather willful decisions that expanded a criminal’s rights to the point where law and order cannot be maintained.
While I agree with you generally, 5th amendment rights have existed long before Miranda.
Miranda simply stated the police had to advise people of them.