It's rare goalkeepers get punished for that sort of thing, and although it's 'obviously' a penalty, even Jamie Carragher said after the match he thought it wasn't, so opinions differ.
It's football, and the PGMOL actually admitting mistakes is much better than nothing from them.
You are never going to get a perfect system, and you are never going to get even the same ref to make the exact same decision, even with simliar incidents, as they may have had a different perspective of the incident each time.
Hopefully in time we will get some ex players involved, that can flag up, 'that looks a wrong decision', for the VAR to then ask the ref to the pitch monitor.. dunno.. obv we don't want to slow the game down any more than it is..
Also in time hopefully we will get to hear the thoughts on an incident in near real time.. may make us understand a bit more..
I'm a Wolves fan btw.. and obviously annoyed we didn't get it..