Why the extreme positions on vaccines are preferred by many

People hate indecision.  They hate confusion. So the simplest way to deal with the vaccine issue is for people to accept one of two polarities.

One of the polarities says vaccines are safe and effective. You can take them without any fear whatsoever and expect them to protect you from whatever disease they are aimed at.

The other polarity says vaccines are unnecessary and best avoided. The reasons given for this may be many. It could be that the person feels in charge of their own health and sees no need for an intervention to protect against diseases they have no fear of.

Alternatively, a person may avoid vaccines because they think they are dangerous, ineffective, or both.

Both of these polarity positions make decision making around vaccines simple.

The people in group one, are happy to receive any recommended vaccine for themselves and their children as they believe them safe, while those in group 2 just avoid vaccines for themselves, and their children, if they feel strongly enough about it.

Those in group one have complete faith in the medical establishment and trust them to make the right decisions on their behalf with regard to vaccination while those in the second group see the medical establishment as corrupt and unworthy of placing one's trust in.

Both these positions suit time poor individuals who don't wish to look too closely into the value of each vaccine recommended to them.

In contrast to these two groups, there exists a third group who take a more moderate position on vaccines, believing they can be useful in preventing disease but that they also run the risk of complications.

Such people need to put more time and effort into researching each individual vaccine and seeing if it is a good fit for them or their child, depending on risk factors and perceived vaccine safety.

As few people wish to put time into vaccine research, most people opt for one of the two extremes, usually the government sanctioned one, as this is seen as making life easier that going against "the flow"- the will of the medical establishment.