Here's the uninsured rate during the Trump and Biden presidencies among the non-Medicare population:
Despite a good economy, the uninsured rate rose 1.0 percentage points under Trump even if you give him credit for the pandemic decline. Under Biden, the uninsured rate has declined 1.5 points so far.
Clearly one can examine data in multiple ways. For me, the meaningful numbers are 10.3% (the rate when Trump entered office) and 9.8% (the current rate. I therefore, attribute .5% to the Biden administration...
Yeah, but that's completely wrong. Trump's administration came in with the intent to kill the ACA and only McCain thwarted them. They cut back advertising on ACA open enrollments and resources to help people enroll to almost nothing. They cut back the availability of the website; as I recall it was suddenly unavailable on Sundays, previously the biggest enrollment day. All of the drop during his administration is on him. He wanted enrollment to be zero.
Whether this was due to his hatred of anything Obama did, or just due to his innate love of cruelty is an open question. I vote for both.
There's less than zero rational justification for that. That's some pretty motivated reasoning there!