@feld @grumpybozo It was exploiting a bug in an MEV transaction service's code, not Ethereum blockchain. It basically could preview MEV blocks on the service, and it proposed blocks that tricked some algorithmic traders into trading good tokens for junk ones that had a trick contract that disallowed trading for those specific bots.

In my opinion screwing over algorithmic traders is just part of the risk/reward tradeoff of that kind of trading. The part where they exploited a bug in a third party complicates things but MEVs right now I don't think have any fiduciary duties or responsibilities.