Well, there's several factors.
One is that science is very important in the modern world, and some people feel the need to have scientific validatation for their faith.
Of course, some people are trying to take over the schools and force them to indoctrinate childrean in their particular sect's interpretation of religion.
And some are secure in their faith and just trying to convert the infidels and heretics who don't agree with every detail of their sect.