There is some evidence that Covid reinfections occur and immunity is not permanent or even lasting longer than a few months. It is premature to suggest that anyone is immune. Even the presence of anti-bodies is inconclusive--I'm sure we all remember that people with HIV have anti-bodies to HIV. There is much nuance to this and the science is still working it out. Again, it is quite possible that each time a person gets re-infected, they will pass the virus on as before. There is some thought that follow up infections will be less severe or even asymptomatic as people have a stronger immune response, but this is also at the level of weak data.
And, for the proverbial record, I am a physician and I am working at a hospital where the research on the vaccine and rapid tests are being done.
I agree with the thrust of your post, though, and agree that we must lead by example.