Someone who introduced me to this forum explained to me back then how he lost everything just by not being careful enough and posting a private key on the proof of authentication instead of a public address and also making the same mistake on the bounty form.
Mistakes happens that's when one is not careful enough and sometimes they are also voluntery action where the posted wants peoples attention to the wallet, in some cases they fund the wallet with huge either ERC-20 tokens which will require anyone who want to move the send in some gas fee which will immediately be moved by the original wallet owner. In some cases, they are addresses, which make use of more than just a phrase to authorize outgoing transactions. I don't know how they do that, though.
Scrolling through the transactions, it's obvious any incoming transaction instantly gets sweeped, usually at a high fee.
I believe in the case of this nature, it's a mistakenly posted wallet, which has many eyes on it, and because of the constant transactions, lots of bots might have been installed to move out all confirmed transactions immediately.