The logic, simply put, is don't blame *everyone* for something that is obviously not their individual fault. Example: Internment of Japanese Americans and the discrimination against people with German backgrounds during WWII. Current attacks on Asian Americans, calling them "Covid" and screaming "Go back where you came from!" Trump's attacks of American citizens serving in Congress in which he told four of them to "go back to the countries they came from." (Ooops... only one of the four was not born in the United States--all four are citizens.) Etc. This is hardly "faulty logic." It's just plain stupid of those who carry out such actions and who hold such biases. Is it my *opinion* these idiots are stupid? Yes. But not faulty opinion. You can disagree, but it's not faulty logic.
As for answering the question, "Where did Covid-19 come from?"... Common knowledge answer from majority of scientists say it came from China, in or near Wuhan, China, possibly inside a wet market. Some theorize it was being examined in a lab near Wuhan and some strain of it "escaped" or leaked out in some way. Very VERY few buy into the conspiracy theory that it was developed there and was intentionally leaked into the population to assist a global cabal in dominating the world. I would say those people have the wheel turning, but the hamster is dead.
As to why it affects the elderly so quickly, I think that's a better question for epidemiologists, not the common folk here at Answerology Reloaded. :-)