Preaching and prayer are two different and closely interconnected things. I certainly don't advocate teachers acting as pastors, and most certainly they should stick to the subject(s) which they are paid to teach, and for the more motivated among them, dedicate additional hours to supporting extra-curricular activities. I cannot see how a teacher could lead a classroom in prayer, and simultaneously distances that from preaching. Were I a teacher and to lead a prayer directed towards Saint Perpetua (as it is her feast day), asking her assistance, I do not see how this could not be interconnected with indoctrinating my students into my faith. Were a Muslim to spout Islamic theology into his prayer, how could this not be a theological subversion of what the majority Christian students were being taught by their parents and church back at home.
Prayer is quite appropriate in times of grief, and on 9/11 my school allowed any student any amount of time off if they asked for it (and surprising me at the time, this was not taken advantage of by the students to simply get out of class). I'm certain that many of them prayed... and I know that plenty of students prayed at lunch that day. This coming to you from Seattle, a true bastion of liberalism, and the heart of the so-called "Soviet Republic of Washington". But would it be okay if as an instructor I were sitting there forcing my students to be a captive audience as I pleaded with Mother Mary to intercesse on behalf of those who died on 9/11? Not in the least - and these students should have the freedom to not be subjected to the religious beliefs and views held by their instructors.
Are you suggesting that I am a city-slicker athiest? Sure, I'm a city-slicker... I came from a major west-coast metropolis, and even today live in a small college town in California. On the other hand, my profession is definitively not "city-slicker" work, and I definitely am not an athiest, no matter how you condemn anyone who doesn't agree with your political viewpoints as a "non-Christian".
I just want for my kids, the freedom of religion - to believe in the manner of their choosing, to pray as they believe, to worship as they are inclined, and to never be force-fed somebody else's religious beliefs. Freedom is key.