Because such a ban would also prohibit all forms of �Kiruv�, which, as seen by the hiloni ruling class, involves socially undesirable Orthodox Jews conducting missionary activities aimed at non-religious Israelis. To most secular Israelis (who are atheists, and very committed to that belief), the Christian missionaries are non-threatening and more amusing and deluded than anything else whereas the frum �missionaries� have a serious record of causing many Jewish youth to go off the zionist derekh and embrace the �yoke of Torah and Mitsvos� (the �yoke� which the zionist anthem sings about being free of). We should remember that to frum Jews, who accept the existence of a creator, the Christians are at least �serious�, but to most secular Jews anyone supporting the idea of a �creator� or �ruler� of the universe is totally off his rocker.
Most secular are not Atheist, but rather NON-RELIGIOUS as opposed to Anti-Religious meaning they arent against reglion in general, jsut that they dont want to be religious