I believe your interpretation of the comments and edits is incorrect.
It wasn't that your question was offensive or touched on delicate sensibilities.
It was your question was unclear.
First, you pointed to an article from Forbes which explained the result of a survey where Americans were asked about their beliefs in a Flat Earth.
The headline (which you quoted) was not backed up by the story itself, because it treated people who selected "Other" as a belief in a Flat Earth.
There was a badly-worded question in a survey about beliefs. A very small number of people gave a ridiculous answer (that they had always believed in a Flat Earth). This is about consistent with the percentage of people who always give ridiculous answers (e.g. the famous legend of 4% of people answering a survey that they had been decapitated).
The article explained how it reached its conclusion, leaving the question of what you needed us to explain about the claim.
You also quoted an article saying 200 people paid to attend a Flat Earth Convention in Britain, which had nothing to do with young Americans.
You asked why people believe in bad ideas, which is largely off-topic here, and was removed.
Ultimately, there is a question of whether a survey or conference attendance accurately captures the true beliefs of the people, but that's a separate question that isn't being claimed here.
Not that none of this critique is because of my sensitivities as an American - not least, because I am not American. But also, because I accept that some trivial percentage of people believe in a Flat Earth, and some trivial percentage of people like to pretend they believe in a Flat Earth, and some percentage of people genuinely have no interest in the subject of the shape of the Earth. There seems little left to explain.