The 'opinion' refering to Article 400 can/cannot is a much debated item here. I see your point; a piece of equipment with a OEM cord as you describe is not an issue in my opinion. If that were the case, then we would have all hard wired pool lights, right?
THe argument is the use of cord as "permanent wiring method"; like wiring from a j box to a strip light; 'drops' in warehouse areas; etc.
No, I did NOT mean break a seal on a sealed pump. All the elevator jobs I have seen have a sump pump receptacle located within the pit, and a note requiring lock-out.