My issue is that why did US health officials say masks were not effective against respiratory infections, when health officials from Asian countries had deemed them effective.
Because Asian countries were basing their advice on science and the US was basing the advice on what would poll well with Republican voters who believe individual freedom is more important than community welfare. The US absolutely did have access to all the science, and chose to (temporarily) ignore it in order to try to gain votes the presidential election.
If Asian countries had been going in to an election and courting votes from a strongly conservative base their advice would have been different.
Because Asian countries were basing their advice on science and the US was basing the advice on what would poll well with Republican voters who believe individual freedom is more important than community welfare. The US absolutely did have access to all the science, and chose to (temporarily) ignore it in order to try to gain votes the presidential election.
If Asian countries had been going in to an election and courting votes from a strongly conservative base their advice would have been different.