The issue? She smacked down Jenny McCarthy (okay, perhaps an instance of using an elephant gun on a mosquito) over the issue of childhood immunizations (McCarthy blames them for her son's autism). Peet apparently said that people who don't immunize their children are "parasites" because they're taking advantage of the fact that nearly everyone else has immunized their children. She has since apologized for the use of the "parasites" word, but hasn't backed off her basic point.
I believe that people who do not immunize their children are freeloaders (my choice of word is a little less nasty than "parasite" but perhaps meaner in terms of judging intentions) — they can only get away with this because the nasty diseases are kept at bay by everyone else being immunized. Yes, there are risks associated with immunizations (autism, though, has been shown again and again to not be one of them); but those risks are very small in absolute terms, and they're even smaller when compared to the alternative: if enough people don't vaccinate their kids (and "enough" may be as small a number as 15%), then we could easily see epidemics of diseases that we thought were conquered in the US during the 1950s.
I predict that within the next ten years, some hyper-crunchy (Waldorf or similar) no-one-here-is-immunized school will be laid low (or worse, wiped out) in a viral outbreak that would have been prevented by simple immunization. I just hope that that event will end this anti-immunization fad once and for all.