Our society is crowded and diverse. Mere knowledge of your heretical belief in that obscene false deity *you* call 'God' is an insult to mine, the *true* God, the one who insists that It is Supreme and that all other claims are blasphemy.
You might think it's innocent to wear a cross in public. Whenever I look at it, I see evidence of deep, awful corruption. I see a person who has turned their back on God (the real One, mine) and by doing so, has denied my God's existence and insults the very streets upon which you walk that It created.
My God insists that I must convert or kill non-believers because they are dangerous. Their fake deity causes them to try to convert or kill. I might be able to resist, but my children are innocent and weak. Heretics will try to convert them, to take them away from the path of light. They might hear of the false, corrupt delights that your fake God offers, heaven or virgins or peace and believe the lies.
I know that you, heathen, feel the same way. You actually think your God is the real one but, since you are wrong, dangerously, blasphemously wrong, my God says I have to avenge Its honor and kill you.
Over your cross.
The thing is, I am right. I should, must protect God's honor. You would be, too.
So, you are a mild person. You think, live and let live. But, I am not and I have the right to religious freedom and it's absolutely *not* extreme to deny blasphemy, to fight heresy, to protect the honor of one's God. It is less common in these soft and weak-willed times. Many so-called believers are too focused on their worldly goods to do God's work but, throughout history, my view, the righteous view insisted upon by my God has held sway.
So, your cross is a provocation. My God says I have to kill you and your God. My God is the absolute ruler and so, you claim, is Yours. My God says that tolerance is blasphemous and so does Yours. That means I must kill you and your false God. No other path makes any sense at all. No other path honors my God as it should be.
It is incumbent upon civilized people to keep their Gods to themselves to keep the peace. Only by doing so can we have a peaceful society.
Oh, you're telling me I'm wrong. I can hear it in your head. "Sensible people do not believe their God insists on the death of the unrighteous. Jesus never said kill the heathen." But, of course, you're wrong on both counts, or close enough.
Sensible people *are* killing heathens as we speak. Their sense, of course, is different than yours but, they can do sums, they can read books, they can run military industrial complexes. If that's not sensible, I do not know the meaning of the word. They merely prioritize differently than you. Or that you would if you were actually devout.
Because, while there is no sign that Jesus said "kill the heathen", Jesus did not have a whole lot to do with the religion that grew up around Him. And, that religion is pretty clear about heathens. And gay people, and women who don't want to have a baby.
The Constitution actually says that the government will not "establish" a religion. It doesn't say anything about allowing religious practices or, worse, providing space for them to occur. The idea that government should not *interfere* with religion, is midrash, additional elaboration by people who think they understand more than the others. Just like those who justified the Inquisition.
A better midrash, a better interpretation, would be to consider that the establishment clause referred to the whole of society, to say that there can be no official religion and that any public expression of religion is an attempt to coerce those who believe in other things.
This would not only have been more correct according to the language of the Constitution, but it would have prevented a whole host of problems. No arguments about crosses on public land, no discussion of whether Moslems can be required to handle pork at work.
All of those questions would be answered, "Religion must not be practiced in public. It is a private thing, between you and your God and your family." You can no more impose your views about pork onto your employer than he can require you be circumcised.
When you are in public, among believers in other Gods, your God is no longer relevant. If that is unacceptable to you, stay home. You have complete religious freedom, there.