When they say private money, what they mean is private banking institution issued currency, sometimes community currencies, or company scrip
What they DONT mean is Shell money, Rai stones, Glass beads, or any other organically forming socially constructed money and that is exactly what Bitcoin is and what shitcoins are not, because shitcoins very much are private monies, but the misinformation that has caused their deep association has caused this type of confusion.