Memes

I think they were talking about the controversial vaccines like the anthrax vaccine, which is one I received while in boot camp

I think the point is that the military, I assume in most countries, can accept a completely different risk picture for soldiers that society at large can accept for civilians. Thus, the military can viably mandate a vaccine that causes severe side effects in e.g. 1/1000 cases, given that the alternative (a serious disease spreading in the ranks) is worse.

Remember that by far most military casualties have historically been due to disease and other conditions not directly related to the enemies weapons. The militaries primary job is to remain combat effective, even if it means mandating a vaccine that is known to cause casualties. This kind of approach would never be acceptable for civilian society at large, where society is deemed responsible for protecting every individual. The military isn't. It's primarily responsible for protecting the civilian society, even at the cost of exposing soldiers to high risk scenarios.

The government functionally owns the military, to the degree that self-harm can be considered damaging government property for service members. Giving soldiers untested medications and injections is not unheard of; i hear malaria medications had some godawful side effects.