Because 40% is a lot. It is irrelevant that it is not most, and the fact that the figure comes from a source promoting that it does not matter makes it more believable.
So what is your point, it does matter or it doesn’t? I already mentioned how your summary doesn’t accurately make a a clear point as to how one can interpret that comment. You have not provided a link to the source.
You have an awful lot of commentary on american culture for someone who doesn’t live here, and for all I know who has never been here.