His reason can be found here:
Wynn wrote in a now-deleted post shortly before the liquidation:
“I do not follow proper risk management, nor do I claim to be a professional; if anything, I claim to be lucky. I’m effectively gambling, and I stand to lose everything. I strongly advise people against what I’m doing.”
Source:
https://cointelegraph.com/news/james-wynn-deactivates-x-account