This is not a precedent in European travel at all.
There are several cases of Ferry fares being different in either direction. This is the case in the Scottish Isles, between Ibiza and Formentera. Even in the UK train fares towards London can be higher than those from
London. When it comes to flights the local departure point can determine a different fare structure depending on the direction.
Sadly, in this case, Ryanair has little to worry about.