Smallpox and polio had been around for years. People had seen evidence of it and had learned to fear it. The death till, especially of smallpox, was staggering when there were outbreaks. Plus, if you got these viruses, you got sick. Badly sick. Everyone. There was never any kind of ambiguity about these viruses.

Covid, on the other hand, is new. There's no history or historical fear of it. It was falsely equated with the flu early on. People die of the flu every year; it's sad but we've learned to live with it. Not everyone gets sick. You can't tell if a lot of people even have it, so for the most part it's out of the public view. All these things combine to make Covid seem like a fake threat; less real to the public imagination. Add to that the state of politics... it's no wonder it became politicized.