Controversial literally just means that there's strong, polarizing disagreement. It's fairly well-defined, and vaccines definitely qualify. This doesn't mean th

Controversial literally just means that there's strong, polarizing disagreement. It's fairly well-defined, and vaccines definitely qualify. This doesn't mean that examining the actual positions of each side would lead you to conclude that they're of equal worth: it just describes the significant disagreement that exists. (As opposed to, say, the heliocentric model)