Reversing transactions is really the only way to protect themselves against (ACH) fraud, so this shouldn't be much of a surprise despite their claims about "no chargebacks".
How does it protect them against fraud? They've still been defrauded out of exactly the same amount of money. They've just additionally defrauded one of their customers. If Jack steals $10 from me, and I respond by stealing $10 from Joe, I haven't "protected myself" against Jack. I've just victimized Joe.