What do you suggest? HODL?
I use stops. You can cherry pick examples where they were detrimental but you can also find examples of where they save you a lot of money.
Here's an example of how stops can be a detriment.
Reminder, these are simple micro-future products. Look at the unrealized P/L swings...
That was from last week, with no stops. Now, if I had a stop at the, say -2K level, it would have been hit. If it was, then I would not have had the reversal back up 1.7K north the next day unless I had entered at the point of the loss. If I had entered at that same level as loss price, I'd still be underwater by the (today) print. By staying in without a SL, my gain/loss has been zero. But the whipsaw is just too insane to manage a position on a day-to-day basis with stops.
And you talk about lessons learned in the "flash crash" (I am guessing you mean the one in 2011 I think?). I kinda' get what you are saying, but when was the last time we had a "flash crash"? Well, 2011! You just have to position yourself where you have enough powder to suffer a sudden drawdown on those rare black swans. This means not overextending yourself.
I am not sure I made sense here. I try. :-(
I got what your saying.