I mean, he basically blames his abdication of the principles of public health on "how science is supposed to work", which is an outright lie. Precautionary principle dictates behavior that he signed on to abandoning and continues to justify refusing to enact. Also, he still refuses to recognize the larger failure, namely trying to spread the disease to the vulnerable in the hopes of a manageable die-off and quick return to normal (10k cases a day in his estimation), the one that's given all his readers a high risk of long term effects, because that's still not very well known. He only admits to the failures that people already recognize, which is defensiveness, not accountability.
Sorry, didn't see this when you posted about it, but some keywords include like the other person said the failure of herd immunity through infection, comments Fauci made more recently about the vulnerable "falling by the wayside", and similar early rhetoric being linked to such views as shown by the UK covid inquiry, something which we are unlikely to ever get in the USA. There, proponents of this viewpoint used the euphemism "dry tinder" to refer to the abandoned and those deemed dysgenic.
The US covid response was basically adjudicated between people who thought we could reopen after two weeks and deal with a short-term die-off, and those who felt a longer runway to the same result would be more manageable for the healthcare system. Much of the deaths weren't seen as worth preventing, only delaying to avoid greater disruption to the lives of more important people. Despite publicly criticizing the Great Barrington Declaration, he has helped them place their policy goals into practice and stayed silent as they failed one by one. Eventually it became the law of the land.
He doesn't really take any accountability for his part in the failure, though. The article is mostly him placing the blame on the Trump administration and "political division"