“How does the body immediately destroy the foreign proteins...?”
The body does it using ribonuclease, RNase. They may have forgotten to teach this in Conspiracy Theory Medical School.
“RNA degradation is a very ancient and important process. RNases clear cellular RNA that is no longer required. Active RNA degradation systems are the first defense against RNA viruses.”
RNA is not a protein; it seems like Texas Troll doesn’t know the difference.
Apparently you didn’t read very carefully this time (benefit of the doubt).