Williamson was an anti-vaxxer before anti-vaxxers were anti-vaxxers.
First, notice what Williamson didn’t say in her apology tweet. By affirming that “many vaccines are important,” she implied that some conventional ones are not—most importantly the MMR (measles mumps rubella) vaccine, which has been found to be effective and safe by every single scientifically valid study ever conducted about it, but which was found to be unsafe by a single non-specialist whose medical license was subsequently revoked, who committed deliberate fraud, and whose completely invalid study was retracted by the journal that published it.
Second, Williamson blamed “Big Pharma,” conflating vaccines approved by (once again) every reputable scientific and medical organization on the planet with Purdue pharma’s latest opiate. This is straight out of the anti-vaxx conspiracy playbook.
Third, Williamson didn’t disclaim her ludicrous abortion analogy. This, once again, is pure left-wing anti-vaxx conspiracy nonsense: that just as we should respect a woman’s choice to have an abortion, so we should respect parents’ choice not to vaccinate their kids.