I've noticed that MD, TCG and OCG all have different banlists, and I'd like to know why?

Like what's the reason the OCG and TCG and MD all have different banlists?

Like seriously why?

Like do people play the game differently in real life and or Japan for it to warrant a different banlist?

If that's the case, then I have this to ask why? Like why do people play differently in MD than they do in TCG and or OCG? What makes them play differently?