That’s because neither of you have ever refereed a game of football. If you had, and it’s irrelevant whether it’s a Sunday League 4th Division game or a World Cup Final, you’d know there are many occasions in every game, where the referee is making a decision on what has most likely happened, rather than is 100% certain of.
Of course at the top end with all the help that brings, you can expect the referee to get more decisions right than a guy completely on his own in the park. But the same principle applies.
If the VAR era has highlighted anything it is how many big decisions in football are subjective.
In multiple games in every round of Premier League games you will see decisions where the VAR will stick with the onfield decision, whichever way it has gone.
If you think every decision in football is a black or white, right or wrong call, you’ve not been paying much attention these last six years or so.