The point is there isn't a separate English Parliament, whereas there is a separate Scottish one. If the English wanted one there is nothing to stop them insisting on it. Until they do they are stuck with a Parliament where all members for all parts of the "United Kingdom" have an equal vote.

After all, so far as I am aware, when there wasn't a Scottish Parliament English MPs didn't abstain on issues that affected only Scotland. Notoriously the Poll Tax was imposed on Scotland as a trial run, before it was imposed on England, agains the votes of the mass of Scottish MPs.