Good religions have strong ethical and moral foundations, but even the best believers don't always behave morally. We are all human. We all miss the mark. However, students need to be taught ethics and the consequences of actions. Perhaps ethics as part of a junior high level social studies class?.
Peer group (ages 6 on up) influence is more commanding than adult (parent - teacher - minister) influence. Peer acceptance is more critical because of lack of adult-child one on one time. Rejection by peers is more trumatic as parent/adult one on one influence is lost.
This also brings up the danger of children rejected by peers and lacking adult companionship seeking out "religious" based alternatives including cults, fundimental extremism etc., as well as the opposite, including gangs, drugs, and extreme sexual behaviour.There are a great many children who can overcome these home-based disadvantages if they have "some" positive role model in their lives. .
The problem can be directly attributed to our economy. This is the reason we have both parents working leaving the child in daycare at the most formative years of life as well as the unstable, dysfunctional family situation which is more and more prevelant in our society. Although the educational system does a reasonably good job of "teaching", it just is not set up to provide the one-on-one role model criteria so needed in developing youngsters. .
Religion cannot step in and take over as it would not have any more "time" to spend one on one than the schools, and, no child can be forced to attend any religious classes or activities (except, of course by parents). Even if this were done everyday after school, you can see the parent/child problem becoming more critical than it already is.
One should not have to "teach" children that murder is a bad thing. This is part of character development and many psychologists say that the first five years are the character development years.