No, it's not. For a while, it was mandatory or else the IRS would fine you (so, it wasn't really mandatory, you could just pay the fine). Now they've dropped the fine. But that's at the federal level; some states still have an individual mandate and will fine you.

You can try to argue that the fine is a mandate, but many people found that it was much cheaper to just pay the fine than to buy insurance coverage. Of course, this means they have no health insurance coverage which obviously has big risks, but for many people, the only insurance plans they had access to were literally unaffordable (i.e., higher than their rent, so it was a choice between having a place to live, or having health insurance with a high deductible and copays).