"It seems they use Entropy and Enthalpy as same definition for disorder."
You need to read the fine print. Referee #1 said:
"This manuscript is concerned with dispelling a non-issue, namely that isentropic surfaces are different to potential density surfaces. It makes basic thermodynamic errors and it should not be published."

The editor said:
"This discussion paper has been under review for the journal Ocean Science (OS). A final paper in OS is not foreseen."

It's important not to make basic thermodynamic errors. Enthalpy and entropy have different units. Enthalpy is not a measure of disorder.

Intuition is fine, but reading some textbooks would help.