Peter Doshi in the BMJ, 2017:

Labeling people concerned about the safety of vaccines as “anti-vaccine” risks entrenching positions. The label (or its derogatory derivative “anti-vaxxer”) is a form of attack. It stigmatizes the mere act of even asking an open question about what is known and unknown about the safety of vaccines.

The label too quickly assumes that there are “two sides” to every question, and that the “two sides” are polar opposites. This “you’re either with us or against us” thinking is unfit for medicine.