Your request to have them explicitly define what they are designating as metadata is wise. They may have a completely distorted concept of metadata that represents a drastic departure from any sane definition.
But the definitions you've put forth are completely off target, with respect to the layman's ordinary, rational concept of metadata. Conceptually, metadata forms a map of relationships between actual examples of data, in the sense that the wires between the lightbulbs are the metadata, while the lightbulbs are the data. Your hypothesis is that someone might propose that only the light emitted from the bulb is the data, and that all other phenomena beyond that are the metadata, so, if you take a picture of the lightbulb while it's switched on, and mark the time, the timestamped photo is the metadata, only because it recorded measurements of the intensity of the photons emanating from the bulb, and did not capture and retain the actual photons themselves (all else, aside from the photons being fair game). No one in their right mind would ever build such an absurd mental model.
The reality is that anyone proposing concepts like the ones you mention, is simply lying through their teeth. Thus, why would you want anyone like that to speak a single word?
If that's their version of the truth, and they seriously believe that's a representation of honesty, it's not worth listening to them.
If they know it's a lie and try to sell the lie anyway, it's not worth listening to them.
If they know what the reality is, but lie and provide the rational definition of metadata, regardless of how inaccurately it aligns with the truth, it's not worth listening to them.
The only thing you'd gain from hearing them speak to their belief of how metadata is defined, would be if you compare what they say to the actually evidence that proves the reality, and assess how warped they are, and how much they lied.