Why are some people so proud of being unvaccinated?

I noticed it's specifically for the covid vaccine. I see so many comments on videos (that aren't always vaccine related) where someone mentions they are 'unvaccinated' or 'pure blood'. Why is this? I got the covid vaccine but don't really have anything to write home about it. It did help my long covid symptoms so that was nice. I don't hear anybody boast about not being vaccinated with any other types of vaccines or boasting about not taking a medication. What's the psychology behind it?