The problem is that the people admitting these mistakes were not necessarily the political figures advocating them to the populace at large. I imagine a fair bit of opposition to the safe vaccines we are able to enjoy is due to skepticism of political figures not owning up to their initial false statements. For example, I distinctly remember the former president stating loudly and repeatedly that Coronavirus was no big deal (paraphrasing), that it would disappear overnight, that the United States was well prepared for it, and so on. I do not recall any mea culpa's being issue: just one new bold statement after the next.
To be fair to our conservative friends, I'm sure this behavior is not limited to only one political party.
Further, many exposés and post mortems are in progress.
The Premonition https://www.amazon.com/Premonition-Pandemic-Story-Michael-Le...
Uncontrolled Spread: Why COVID-19 Crushed Us and How We Can Defeat the Next Pandemic https://www.amazon.com/Preparing-Inevitable-Normal-Survive-E...
Preventable https://www.amazon.com/Preventable-Leadership-Failures-Selfi...
Move on.