Earlier quoted context omitted.
It would be deeply funny if SparkFun was referring to Adafruit forwarding inappropriate emails written by SparkFun employees to SparkFun, in an attempt to report their harassment.
That is exactly how I understand it at the moment. And depending on the material, it would be a somewhat valid complaint, if the report included the material without prior warning. Though, not valid enough to call CoC on this, IMHO.
Saying that you’re required to give a content warning to an account manager for material related to your business relationship puts the burden of responsibility onto the victim. Dealing with the psychological impact is the responsibility of their employer, not the customer.