I see they recovered. You're correct... One interpretation could be that a high percentage of X-factor was present in this study's recovered group. But since we don't know what the X-factor is, an unvaccinated person is rolling dice by assuming they have it.

Nothing about this study guarantees an unvaccinated individual survives a brush with COVID-19; it suggests they're likely to survive a second brush with it (and likelier still if they get vaccinated).