Sulfites, potassium sulfite, k-meta... One in the same
In the beginning of the winemaking process, k-meta is used to prevent wild yeasts or bacterias from competing with your chosen yeast strain - it basically shocks everything into temporary submission, which is why its recommended to wait 12-24 hours before adding your chosen yeast so that it doesnt get shocked too.
When wine is bulk aging, k-meta is used to keep oxygen away - oxygen will ruin/spoil the wine. When you add k-meta to wine, half of what you added becomes "bound" within the wine, while the other half is ready to dissipate at the first chance you get - this is why wines that are bulk aging still have airlocks that bubble.
When you're bottling, you want to check your k-meta levels within the wine in question so that while in the bottles, theres enough k-meta to keep the oxygen at bay, because corks are porous and do breathe, albeit slowly.
If you opt out of k-meta additions, it comes down to being sterile in every step of the winemaking process & not violently stirring/racking/agitating the wine to introduce oxygen... This is pretty tricky for the home winemaker, and is a bit of a gamble unless you're sure of your methods & cleanliness.. Even then, its still a gamble for most.