An individual who wore a livesuit rather than contract immunoflu flies to a planet suffering from a global plague, evading the quarantine, to try to "prove the plague is a hoax" and that "introducing immunoflu here is what will kill everyone". Needless to say, the moment they removed the suit and got infected with the plague infecting the planet, they learned they would be spending a lot of time in the ICU. -- Lessons
Ignorance is one hell of a drug. Willful ignorance doubly so. An individual just decides on one absolute inviolate truth and refuses to learn different. It has killed thousands. Millions, even. It's about to kill one more.
People will go to any lengths because of a belief they themselves carved in stone. Human Nal, of the Pure Life Aggregate, was fully prepared to die for her cause. If people just stopped using the hideous pollution of the immunoflu and lived clean lives, she reasoned, there would be no more disease. Then all the Mediks and people making more hideous poisons called 'medicine' could relax and only treat injuries.
As far as beliefs went, it was nebulously wholesome. Whilst everyone had the right to proper nutrition, and the CRC fought for everyone to have access to the same, not everyone can afford to have those nutrients from natural sources. The fact that everyone can get such things only in theory has passed over Nal and her fellows' heads by a significant margin.