I mean, having a healthy diet, eating "clean", doing exercise, cutting back on alcohol and smoking, and generally being healthy, are all good ofc. Taking some supplements to boost immunity is also possibly a good idea. And more power to you if you do live that way, because that means you're healthier than I am haha. So keep doing that. (I'm being totally sincere here btw. No sarcasm intended whatsoever. Be healthy. I'm not gonna criticize that. You're doing better than me.)
I don't dispute that for a moment.
But we're talking about deadly infectious diseases here. "Natural immunity" will get you so far. But the human body is not invincible. Humans aren't immune to every illness. If we were, disease would have never posed an issue throughout our history and countless people wouldn't have been wiped out by epidemics. Our natural immune system is incredible, yes, but it can only handle so much. Until we developed vaccines and discovered penicillin, etc. You can be the healthiest bodybuilder on earth living on a raw-food organic diet, but if you catch Ebola, you can still die. That's the problem. And that's where medicine comes in. (There were even a couple of famous cases of anti-vaxxer influencers saying this kind of stuff who DIED of Covid. I find that tragic. When a vaccine could possibly have saved their life.)
If there is an Ebola outbreak in your community, what do you think will protect you more: taking supplements and being healthy, or taking a vaccine?
Tylenol/Aspirin may lessen symptoms, yes, but they have no effect on your immune system. They only work on symptoms. You have a headache or hangover or flu? Tylenol reduces the symptoms, yes. Does it actually help you body fight the infection/fix the problem in any way? No. Tylenol doesn't actually fight infection or strengthen your immune response.