It should be said that the staff at OKX are still very responsible and gave me a lengthy explanation of the reasons behind this issue. I have also roughly understood that the key point is the liquidation fee for forced liquidation, which refers to leveraged trading, including futures and options. As long as there is a short position, an additional "forced liquidation fee" will generally be charged, objectively causing additional losses for leveraged traders. Putting oneself in the shoes of others, the person who caused the collapse was already in great pain and was charged extra. Salt was sprinkled on the wound, which was indeed somewhat unnatural. But it seems that cryptocurrency exchanges all have this fee, and whether it is illegal depends on the relevant laws and regulations of the exchange's operating region or the investor's location. As for those charged liquidation traders, they probably agreed to the so-called rules of the exchange without even looking. Here, I just want to say that if you don't have the ability, don't touch those high leverage products, especially futures contracts; One should take this as a warning even if one thinks that being an option seller has a high winning rate. Serious consideration of options, many options combinations can achieve high leverage without the risk of liquidation. (Don't think it's just one leg, it's too low, theta deck will kill you)