“Why should my Health Insurance be affected by bad decisions or even unknown circumstances that others encounter?”
Because that is what insurance is. It’s a risk pool.
As an aside, its almost certainly cheaper to give everyone a $112 shot (and that’s the retail price, probably 1/3 that if you are in a big pool) than the millions it cost for cancer treatment per person.
At 7,000 per year, assuming $1 million (conservatively) for cancer treatment that that’s $7,000,000, 000 (7 billion per year).
It’s certainly cheaper to prevent the disease.