What makes health insurance so "unaffordable" and to "expensive"?

Is it the doctors who still have student loans to pay off? Is that why they're incredibly expensive? Why?
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There are many reasons, including; Indigent care, malpractice lawsuits, pharmaceutical profits, taxes, uninsurable people (like me; private health insurance is way too expensive for me due to a preexisting condition that is actually quite easily controlled), license fees, and that's just a start.
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