Because before 2020, natural immunity to virtually any infectious disease was considered sufficient and superior to immunization. The entire concept of natural immunity being "not good enough' is brand new. It was never uttered before COVID, and it has never been proven even during COVID. It's an absurdity, that nobody in the realm of infectious disease even entertained before government started acting forcefully on behalf of pharmaceutical companies in the past 18 months.

Go look for yourself. "Do I need varicella vaccine if I had chickenpox?" The answer is NO.

>Oh, this is a different disease

Okay, then produce a single study indicating that those with prior COVID infection are hospitalized with a reinfection at higher rates than the fully vaccinated. That study doesn't exist. It's all just arbitrary anti-body level response studies, which are useless. If you can't produce a study to show why this infectious disease should be treated differently than all the others, then we'll go with the default position: natural immunity is enough.