convinced 11 different women that 'he had no roster'

If a guy uses "roster" in that context, regardless of it being an admission or denial, it means he's familiar and comfortable with that terminology. Which means he either has one or thinks its fine.

And the reason you didn't think it was a red flag then was because you are also comfortable with the idea and probably have your own. Everyone involved got what they deserved.

Ask a normal guy if he has a "roster" and he'll probably think you're talking about fantasy sports or something.