If all they did was "try to find out" and then letting me go when they are either satisfied or I stop talking and they have no probable cause a crime has occurr

If all they did was "try to find out" and then letting me go when they are either satisfied or I stop talking and they have no probable cause a crime has occurred, I would have never made this post. It's clear to me these lists are as much about extra-judicial punishment as "finding out." I do not think a place exists in our society for these lists that impose against the freedom of citizens to travel without some sort of due process to petition a court for removal and/or some way to "drop off" the list after X years of living as a free peaceful citizen in harmony with others. Law enforcement officers should be tasked with enforcing the law, not with harassing people about things that are non-criminal, like fighting against ISIS (believe it or not there is no law that prevents you from fighting in a foreign militia, and in fact I do not believe any American has ever been charged for fighting with YPG.)