Religious Freedom

I am very much in favor of religious freedom, as well as freedom in general.  But we must determine where to draw the line.  There needs to be some limits to nearly everything in life, healthy boundaries.  How much religious freedom is too much, and who should determine that?  I think most of us would agree that child sacrifice crosses the line, but then again, abortion exists.  But for the sake of argument, let's assume that there was a religious sect that sacrificed all their male infant children in fire, as part of their religious beliefs.  I think we can agree that it would be acceptable for the US government to outlaw that practice, but making something illegal doesn't prevent it from happening.  So what should our response be when it does happen.  If the perpetrator doesn't deny the crime, and has no remorse for their actions, what should be done with them?

No fine or other basic penalty will prevent them from continuing that practice.  We could lock them up forever, which would stop them from continuing to kill infants, but what purpose does it serve for them to be alive in jail?  If we release them in the future, they would openly return to their previous ways.  Killing them seems harsh in our zero consequences culture, but logically seems fitting, based on their crime.  But that would amount to genocide if all strict followers of the religion were found and convicted.  And we have been taught to assume that is bad, but what are the alternatives?  (Endless conflict, violence, and suffering)

We have a similar situation with the rise of radical supporters of the Islamic State.  Their openly confessed religious beliefs are that God wants them to kill all infidels who do not join their cause.  This is different than Al-Qaeda, because in that case the challenge was identifying those who supported them in secret.  Once they were identified, we didn't hesitate to lock them up or kill them.  But now we have many people who are openly aspiring to follow that violent path, like the American recently apprehended in Turkey.  What should be done with people like that?  They haven't necessarily committed a crime yet, but they openly hope to take part in all sorts of brutal activity.  How should we respond to situations like that?

Should he make it a capital offense to advocate or promote killing Americans (also known as terrorism)?  If someone's anti-American beliefs are so strong that they won't recant them under threat of death, should we just kill them?  Faith is not an inherently good thing, apart from truth.  God condemned faith in false gods in the Old Testament.  Strong faith in ideas or principles that are false is dangerous.  But how should we respond to the misplaced faith of others, especially if it is too strong to be broken?  We can’t prove that we are right and they are wrong.  But shouldn't the right to self-defense over-ride the right to the free expression of religion?