Making up shit and taking everything out of context to make things sound horrible is exactly how people who think Marche is a complete villain is exactly why the game has the retarded reputation it has today.
The only point you have correct is that Marche didn't attempt to find a portal back to his own world via the magic that is inherent in the world at that moment, but he was also trying to go get his friends and family and bring them back WITH HIM to the real world.
He also believed (for the wrong reasons, but correctly) from the start that the world he was in was not only a false reality but also replaced his own original world and all his loved ones except for two nerds and his crippled brother. So taking a portal back to that world would do nothing as there was no world to return to.
“This world is illusion. You can hold it in your hand and still be holding nothing.”
Actual quotes from the game saying so.
The grey part of the argument comes from HOW Marche approached his goals, and the philosophical argument that an illusion can be real if it feel real enough. But even then, all of his friends were just as big assholes about stopping him as he was about bringing them back.