One simple reason: fuck insurance. Seriously, I'd rather the money I pay in (and don't EVER use) to pay for someone with less luck, skill, brains, money, whatever to get treatment they need than line the pockets of some awful peddler of broken promises.
No matter how you slice it, you're paying for health care. Wouldn't it be great if the money I'm pissing away on insurance I don't use could support the needs of someone less fortunate?
And if you say my premiums are paying for health care of other insurance participants, then make insurance companies non profit and standardize the cost of services.