I think where people get into trouble with unsanitary conditions is when they have equipment that they don't clean carefully after making a batch. The old wine, fruit, or juice attracts bacteria or molds that are attracted to wines. It's these nasties that can ruin your wine. Some of the average household germs that are just lying about aren't so much of a problem because they're not suited to living in a high acid environment, or the alcohol kills them off, or they don't eat fruit juices. Also think of all the germs you introduce with natural fruit. The peaches that the winemaker crushes aren't sterile on the outside; but most of the things on the outside face an uphill battle with the addition of K-meta, sugars, acids, and fermenting yeast. Keep your equipment clean from previous batches and you've won 90% of the battle.