I really think it's more accurate to call upper-class POPs "aristocrats" rather than "citizens." In a Roman context you had plenty of citizen farmers and plenty of non-citizen landlords, and until the late principate citizenship was a special privilege handed out to non-Latins on an individual basis and not something that could just be "promoted" into. I think the terms they're using here blur legal and economic status too much.
And then the hellenes would look silly with 1 aristo pop and the rest mostly freemen and slaves and research stops dead.