Similar to the vaccine, having natural antibodies isn't a 100% effective solution. "So-called experts" aren't ignoring it and are actually studying the effect of natural antibodies. No argument from me that natural antibodies do exist. Having said that, your original post was questioning the effectiveness of vaccine passports. A couple weeks ago my friends and I went to a bar downtown on King Street. There were 11 of us, 6 fully vaxxed and 5 unvaxxed. A few days later we found out that there was a covid breakout at said bar. Of the 5 unvaxxed, 2 became moderately sick and the other 3 were incapacitated for a week. They all said it's the worse they've ever felt. Luckily, no one had to be hospitalized. Turns out, they had all contracted the delta variant. Out of the 6 of us that were vaxxed, one contracted the delta variant and had very mild symptoms. The rest of us tested negative and felt completely fine. So if the goal is to prevent widespread transmission, hospitalizations and further lockdowns, then yes, the passport will be effective.This is not entirely true. There is such a thing as natural immunity. Something I learned quite a bit about in Virology class at UofT. However, it's something for some reason being ignored by the so-called experts. Technically those unvaccinated people who've got covid-19 and recovered have developed natural antibodies. You can actually get a SARS-CoV-2 antibody test at a private lab like DynaCare and your results will show you have antibodies not due to vaccine. So first of all these vaccine apps should also recognize those with such proof as amongst the "vaccinated". However, the only distinctions they make is vaccinated, partially vaccinated, and unvaccinated, and that is wrong. Second of all you make two incorrect assumptions:
1) that the 1/4 unvaccinated do not carry antibodies against the virus, there are many in this group who have recovered from covid-19 and have immunity
2) that the 3/4 vaccinated carry antibodies against the virus. A lot of people who were vaccinated around January 2021 may no longer have antibodies to protect themselves and technically should be labelled as "unvaccinated", hence why they want to have them get a third shot
The vaccination stats shared daily are not completely accurate so what you say about 3/4 of the eligible population being vaccinated is not exactly true.