This is mostly right but: It's certain strains of lactobacillus, not yeast. Yeasts are probably-to-certainly present in small amounts in fermentation but they

This is mostly right but: It's certain strains of lactobacillus, not yeast. Yeasts are probably-to-certainly present in small amounts in fermentation but they aren't critical to its success or failure either way. The containers should be clean, no biofilms or visible grime obviously, but wash-rinse-air dry is plenty. Clean enough to eat off of. The fermentation lactobacillus are tolerant to salt and will dramatically outcompete everything else in a salty environment. The careful sanitization is for brewing where the yeasts don't have this advantage, or canning where botulism complicates it. For fermentation alone it's not a concern. The vegetables on the other hand you don't want to clean too meticulously. You want them clear of dirt, debris, bugs obviously. But the bacteria you're using to ferment are naturally present on the vegetables and it is the only effective source of them. You can see this with ginger, a lot of which is irradiated, virtually bacteria-free, and notoriously inconsistent to ferment alone for that reason.