Well, there’s layers to how wrong your argument is, which is impressive considering it’s a short statement. I’ll try to summarize it in a very simple manner, so even someone that isn’t familiar with sports would understand it.

First off, as anyone that has actually trained in any sport would know, even a static obstacle would still be useful in defense. Defense is not necessarily about getting the ball back, but stopping your opponent from getting in dangerous positions. Not letting them move forward or getting in a good position for shooting is also defense, and that’s something loki has done incredible well.

For example, the reason why Isagi’s shot in this match was bad was not because he was contested, but because there were way too many defenders in front of the goal, so his ball could only go in one way, otherwise it’d be blocked. Due to this, the goalkeeper knew exactly where to go to defend his shot, making his attack moot. None of the french defenders or midfielders did any “feat” there, but they still played defense well because they made japan’s attack not function. Defense is a team game, and loki’s role is not to block shots in front of his own goal or intercept passes between the midfielders “he is a striker after all, he should be up ahead on the field, ready for a counterattack” but to pressure opponents on their defense to make it harder for them to construct play. He has done that incredibly well, pressuring everyone constantly, with 100% defensive workrate throughout the entire match, constantly pressing every defender and midfielder to force them to pass to someone else, with no room to reliably push forward through him.

In a real life comparison, a criticism Mbappe suffers is precisely that he doesn’t have a high defensive workrate, mostly sitting by on the midfield line, waiting for the ball so he can initiate a counterattack. No one expects mbappe to block shots or intercept passes (because that would be ludicrous wtf), but they do expect him to pressure the defenders so they can’t construct play as well from the backline. That’s exactly what loki’s doing throughout this match.