No, no you do not have to wonder...
It is not just the attitude which was exhibited above that is a problem, but there are an entire host of other associated things which contribute to the problems involved in getting a handle on the coronavirus in the US. There are some segments of the US population, often very religious and conservative (IMO less conservative, esp now, and more regressive) which have at times controlled what is taught is US schools, and still work to exert or re-exert such control. Among the aspects of education that have actively worked against, is the teaching of science. BTW this is not a new situation for the US, since Tennessee v. Scopes, known more commonly as the Scopes Monkey Trial, took place in the state of Tennessee in 1925, nearly a century ago. This taught and indoctrinated ignorance, as well as a taught inability to engage in critical thinking. A case in point was back in 2012 when Texan politicians opposed Higher Order Thinking Skills (aka critical thinking) from being taught in Texas schools on the basis that they would challenge student's fixed beliefs and undermine parental authority.
With such a background, and now in the foreground political and religious "leaders" having been stating opposition to vaccinations as well as mandates for mitigation efforts, it is little wonder that the US is now in another wave.