Read this to find out about Hitler:
http://www.mega.nu:8080/ampp/pinkswastika.hold/book.html
Of course horrible crimes have been committed in the name of religion. In the case of Christianity, it's not God's fault or Jesus Christ's fault, it's the fault of fallible people who either were using religion as a cloak to commit atrocities.
Islam, OTOH, seems to have tenets that mandate forcing itself on others, so that's a different situation.
Anyone can call themselves a Christian, Jew, Hindu, Buddhist, or Sikh. Doesn't mean they are living up to the codes and teachings of their religions, or that they are even sincere. Some are just crooks, scoundrels or criminals; wolves in sheeps' clothing.
It sounds as though you know very little about what the founders of this country actually thought and believed. How about this one from Jefferson:
"Reading, reflection and time have convinced me that the interests
of society require the observation of those moral precepts ... in
which all religions agree." --Thomas Jefferson
And those moral precepts are remarkably congruent.
Should read:
"the fault of fallible people who were using religion as a cloak to commit atrocities."
Lets not start a quote war here...You would not like that. I am very familiar of what the founders thought and believed. Jefferson was a Deist. He improved the King James Bilble by editing out the crap. He considered Jesus a great Jewish teacher, but held no respect for the religion founded in his name. Read the Jefferson Bible.