I think it is being drummed into them that if they do not follow what they are being grown up on in school,... then they are being thought of as stupid. And I think that being thought of as stupid and being ridiculed is somethign people try to avoid. This happens when they are young and their opinions are still forming.
i get the impression this happens just as often in sunday school as it does in public school. but if one has an opposition to secular education then one should take hir son or daughter to a school that doesn't offer a secular eduction. but when a secular government offers education it will be taught on secular terms. or at least it should be.
as for secularism, the reason everybody loves it is because the religious and the irreligious can both share in it's benefits. and these benefits are precious to both.