I think most of these folks were young and made a choice not to buy insurance because they didn't see value in it. Others who wanted insurance went without it because they figured they would rather spend their money on something else.
The ones who really, truly needed it but couldn't afford it already had a choice.....medicare or medicaid.
Obamacare was never about insurance. That's how it was sold. It was cover for massive tax increases and a blatant money grab by the fedgov.