Elo is not a matter of opinion. There's a formula for it, and 28 wins, 72 draws and 0 losses represents almost exactly a 100 point Elo difference.

https://www.3dkingdoms.com/chess/elo.htm

You are right, thank you for the pointer.

I guess that the spectacular 28-0 was somehow confusing my ELO opinion engine by concealing the fact that 72 draws are a lot more difficult to achieve than 12 draws (28-12-0 would have been a 300 ELO difference).