Proselytizing of any shape or stripe should be viewed with a raised eyebrow and a challenging question. When this proselytizing is based on what one might charitably term pseudoscience (but truly resembles complete quackery) we should not simply be skeptical, we should be incredulous.
Jenny McCarthy is entitled to her opinion and her mommy instinct, but she's not entitled to the validation and amplification that come with a job as a daily blogger for the Sun-Times. As Maria Puente writes at USA Today, "She definitely has a voice, and now she has a megaphone."
Why would Mr. Trump do this? Why would he carelessly extend a wildly unpopular theory amongst researchers to a public that may not be aware of the actual science and decade-plus amount of work that have gone into discrediting the link between vaccines and autism?