Saltpeter in curing was not a common occurrence. It was first massively used to make fast and cheap cured meat for the navy in the 1700s-1800s.

There's a lot of corporate propaganda about the benefits of nitrates which are all lies. People naturally cured meats for thousands of years without botulism and suddenly we all gotta start using nitrates to prevent it?

The reason they want to normalize nitrate curing is because meat processors can then have lower hygiene and quality standards, meat cures significantly faster, and the process gives meat a red/pink colour which sells better.

Do not believe their lies.