Well, let me restate that I only clean in the washer with bleach, and have never had a problem either. However, I don't think killing stuff is the issue with bleach. The thought is that bleaching leaves dead organics behind that can break down in the water when returned to service. I don't know how much, or if it could even be enough to matter.
When I looked into using HP to clean socks it seemed too expensive for the possibly marginal benefit. This is why I have stuck with the simple method - Plus I hate cleaning them - so in the washer they go!