The natural born citizens dissatisfied with the US are generally not comparing the US to a developing country or a country with an ongoing war on their soil, which is where most immigrants come from.
Instead, they are comparing it to other developed countries and focused on specific conditions that matter to them, like housing, transportation, environment, violence, etc.
> Yes there are problems in America, but how many of those problems are the result of an apathetic, nihilistic American population and not the foundational systems America is built on?
The criticism of these problems is far from apathetic, and it's an important part of how we begin to remedy them. For example, we aren't going to wish away gun violence by ignoring it.
The biggest current threat to the US isn't this criticism, but rather the attack on its democratic foundations happening now. However even that is not coming from apathy, though its goals are very nihilistic in the short term and oligarchic and theocratic in the long term.