Maybe because it was an irrelevant deflection?
From my understanding of the prevailing science, the immune response boost provided by vaccination following natural infection is superior to natural infection alone, benefitting each individual person as well as the collective community trying to minimize all the negative impacts of any pandemic. So I'm in favor of doing things that encourage maximum participation in vaccination, whether previously infected or not.
It seems that the future protection provided by natural infection alone is quite variable depending at least to some degree on the specifics of the infection (length, severity, perhaps strain) as well as recency, and each person's own physiology. Of course, the degree of protection provided by vaccination is also variable, but at least we have vax records to prove when we were vaxxed and by what specific dosage of which vaccine, so there's a bit more consistency than when dealing with self-reported natural infection, description of symptoms, etc.
There are also many logistical complexities to determining past infection (if you're not merely relying on the honor system) not the least of which is the higher cost and higher scarcity of FDA-approved antibody tests that haven't already been recalled, and all of which require blood draw to the best of my knowledge.
I'm not against using prior infection as some indicator of probable immunity (which is not limited only to the fighting-off-infection aspect of immunity), as long as it follows the prevailing understanding of the science and is actually practicable, both economically and logistically in whatever real world use for which it is being contemplated.
Here's a great discussion of immunity, and what scientists have learned and continue to learn from our Covid-19 experiences. Unfortunately, it's probably too TLDR, nuanced and complex for most folks on a message board who just want a quick pro or con take they can slap on a meme.
Immunologists have raced to work out how to protect against multiple variants of SARS-CoV-2. Their research has yielded a wealth of insights and a few surprises.
www.nature.com