The point is not at all moot, because a claim was made that the Constitution "explicitly" forced the Free States to consider slaves as property. That claim was false, and I'll just continue to stick with the actual wording rather than with any "pet term."Your point is rather mute, as whether one wants to call them property or not is irrelevant to the law and constitution, because both considered them bound to service. So if you find indentured servant for life more PC or it fits your agenda more then slave or property, by all means use whatever pet term you prefer. If you wish to sugar coat slavery or that they were property it's noted, personally see little need, as it was what it was.
But what's relevant to the OP, is to the constitution they were bound to service, and according to the US Constitution another state could not relieve or free someone from that service, and were to turn them over to those or whose agents the service was due.
One doesn't to have to either approve or like a law to understand the laws actual meaning and intent. Least most people are capable of making such a distinction.