Okay. I already acknowledged that options are a good way to blow up. You'd think Op would mention options if that's what happened. It's not a common definition of day trading. Trading stocks it is almost impossible to reach 0 unless you're basically trying on purpose to lose it all. Maybe Op misspoke about the "not a dime" thing and what he actually meant was that the guy lost most of his money, like 70% or something before he decided to stop. Plausible. But when you combine it with the other things I think my skepticism is still justified.
BTW In my experience I lost way more money on buy and hold than I ever did on trading. The majority of stocks eventually go to $0, especially small ones, so if you have no picking skill you will just lose and lose and lose and lose more while you sleep. If your only plan is buy and hold then you have no logic for exit other than emotional pain of huge losses. If you are flat at the end of the day you need to work to lose and it's easy to stop. It forces you to evaluate your decisions every day.
Fair point. It is quite a small number of trades so maybe the 6 years experience doesn't mean as much as it normally would. But it should be enough time to give a feel for volatility, and discover that you shouldn't be putting like 50% of the account on a single stock. I mean, the level of stupid risk needed to get an account to 0 is pretty hardcore. Assuming it's a true story I don't think this was a lack of understanding of risk management, but more likely some kind of gambling addiction / compulsive behavior.