I think the parent's response is clear, and that they should not rephrase it. In fact, I'm having trouble rephrasing it (without having to explain what "group identity" is).
Here it goes, nevertheless.
People are social beings. We like to find "our" groups, and feel pride in being members of them. Examples of such groups: political parties, nationalities, religion, fans of a particular kind of music/artist/clothing style/tv show, hobby groups, etc).
Because of that, we feel bad when our groups are conflated; we feel it erases a part of our identity. Waged workers in this example feel pride in being not slaves, however nominal the distinction is.
This effect is even more pronounced because in a stratified society (which the Roman Empire was), as a waged worker, you could be confused for a slave, but not for a member of nobility. (We feel the most animosity when being taken to be a member of a group that resembles ours the most. Tell a Ukrainian that culturally, very little differentiates them from a Russian - and be prepared to be lectured on just how wrong you are.)
So, waged workers, then and now, would have reasons to vehemently identify themselves as "not slaves", and thus they would be biased in assessing the differences, seeing all of them as significant.
Here it goes, nevertheless.
People are social beings. We like to find "our" groups, and feel pride in being members of them. Examples of such groups: political parties, nationalities, religion, fans of a particular kind of music/artist/clothing style/tv show, hobby groups, etc).
Because of that, we feel bad when our groups are conflated; we feel it erases a part of our identity. Waged workers in this example feel pride in being not slaves, however nominal the distinction is.
This effect is even more pronounced because in a stratified society (which the Roman Empire was), as a waged worker, you could be confused for a slave, but not for a member of nobility. (We feel the most animosity when being taken to be a member of a group that resembles ours the most. Tell a Ukrainian that culturally, very little differentiates them from a Russian - and be prepared to be lectured on just how wrong you are.)
So, waged workers, then and now, would have reasons to vehemently identify themselves as "not slaves", and thus they would be biased in assessing the differences, seeing all of them as significant.
Ranks of nobility would have no such bias.