Ah, that's what I call street objectivist logic. Biology is not the only relevant force here. Do you think it a coincidence that most people believe the same thing as their parents? We are biologically designed as to trust our parents, as that is essential to the survival of the species. Living in certain environment for a prolonged period, specially in formative years, makes defection a challenge. Depending on how religious the family is, coverting (or deconverting) can have significant impact on personal (and business as is sometimes the case in LDS religion) relationships. It is not as simple as you seem to have convinced yourself.
Additionally, neither biology nor choice bear a connection to how offensive something is. Being offended is an emotional response. Most would be more offended if someone called their spouse a loudmouthed b, than if they mocked their height by asking them the weather "up there". The first is an offense on your choice (in marriage) and your spouse's. The second is mocking an out of your control biological trait.
Point is, people can make fun of whoever they want. The idiot journalist has the right to attack the Mormons, and the all the Mormons can do is accept it (or complain to deaf ears). Fact remains, he comes off as an unprofessional douche.