The UK leaving the EU is seen as a UK failure (because brexit affected the UK much); but them leaving the EU is a EU failure because one of the members of the union has left. People underestimate this fact a lot.
How would have the EU prevented this when the Leave camp was fueled by lies, such as the famous NHS budget bus and all the various Euromyths that the UK press liked to conjure? It's not like people didn't try debunking them.
