At the margins you will always get controversial decisions. How can there possibly be an exact moment where hands are in a natural vs unnatural position? Now account for changing direction and speed of different body parts, the distance the ball is struck from, the speed of the ball, other irrelevant factors like where on the pitch the players are…
Fundamentally close decisions will always rely on judgement and reasonable people can disagree. That’s the nature of the sport. Nothing will ever change that.
Managers and the media instrumentalisé that and they have a captive, highly emotive, highly biased audience. This makes dozens of calls a game potentially controversial when really you have good faith referees making extremely fine judgements under immense pressure. Adding fuel to the flames doesn’t help.