The reason I heard they do this is because the virus presents itself first in the nasopharynx in the head without causing any symptoms in the infected person. By the time it has spread to/reached the lungs or the rest of the respiratory track it already starts causing symptoms.

NO. That is a fake news lie.

There has never been one case of asymptomatic spread ever identified. Not one. If you don't have symptoms, you can't spread the disease. The idea that the magical swab to the brain is "catching your infection early before you, a disease entity, can kill grandma" is a fucking deepstate globalist LIE.

Not blaming you, rather the deepstate for spreading this misinformation.