I can recall from my own experience in 1957, several Adventist children left the classroom during prayers. Are Adventists liberal? Your assumptions as to why people consent to things is way off base. Just because people aren't marching in the streets doesn't mean they agree with everything going on.
Let me re-phrase: There was no constitutional dispute before mid-20th century. Prayer in school was accepted for 200 years and no one questioned its legality. Congress even printed a bible for schools in 1780s (egad!). Then there are the real founders of our nation - the Puritans (who invented universal education btw) - who taught from the bible in schools. Schools now are nothing more than indoctrination centers for atheism and libertinism.