Not through any fault of their own, but to use a quick analogy, it's similar to The Emporer with No Clothes.
You did what you believed to be the right thing, but wothout regular antibody testing, you have ZERO knowledge on how the vaccine truly affected you and how strong your immunity is or isn't, yet you continue on with an invisible armor with the assumption that not only are you protected, but that you're protecting others when it might not be true
That's not a very good analogy - in The Emperor's New Clothes, it's a scam. Anyway, your analogy would hold more water if people getting the vaccine were relying on faith and buying snake oil. But they're not. Any single vaccine recipient may not have any particular knowledge of their immune status, but they are lucky enough to be able to rely on documentary evidence. This isn't blind faith, it's a decision based on a significant body of scientific knowledge.
The vaccines are known to be effective, even if the efficacy is diminished in respect of the Delta (and Alpha and possibly other) variants. And antibody testing only shows the presence of antibodies and has no way of determining how much immunity you possess. As I type this, I am working on the basis that you have not yet got your antibody test results. So you actually don't know if you have ever had the virus. If your results come back positive for COVID antibodies, that just means you have had the virus and have antibodies in your bloodstream. It says nothing about how much immunity you have (or which strain infected you, etc).
And who's to say that any person choosing to get the vaccine isn't ALSO in possession of COVID antibodies from a prior asymptomatic infection? I think one odd thing about your analogy is you seem to be the one who is putting faith in something you have no proof of (both the robustness of your immune system and how it would respond to a SARS-CoV-2 infection as well as the fact that you *might* have had a prior infection). The people choosing to get the vaccines at least have clinical evidence in support of their position (even if the evidence is less than complete, it's astronomically more extensive than what you're going on).
Maybe you were using 'you' to mean 'one' - but in my particular case, I got the vaccine and have not changed my behaviour since the beginning of lockdown. I barely leave the house, I avoid public transport and I wear a mask if I have to be indoors around people (grocery store, train on the way to work once a week now that I am being required to do that). So, no acting like I have an 'invisible armour'.
Anyway, getting the vaccine and having natural antibodies INCREASES your immunity. By choosing to forego the vaccine, a person is deliberately choosing to reduce his immunity.
If you have concerns about the vaccine, then maybe just say it? You've not articulated any particular concerns about the vaccine (at least not that I recall seeing in this thread). So as it stands, your argument seems to be, "I think I've had the virus, so I don't think I need to get the vaccine".