Because to make that argument, you have to reduce the definition to the point of uselessness. Jurassic Park isn’t Isekai/Stranger in a Strange Land because the island isn’t a strange, unknown land. It was created by the same people/culture the main characters are from. Isekai needs an independent culture with it’s own history and people.
But then SAO also isn’t an isekai because all it’s inhabitants are just visitors from the real world and was also created by the same people/culture the main characters are from
Because to make that argument, you have to reduce the definition to the point of uselessness. Jurassic Park isn’t Isekai/Stranger in a Strange Land because the island isn’t a strange, unknown land. It was created by the same people/culture the main characters are from. Isekai needs an independent culture with it’s own history and people.
But then SAO also isn’t an isekai because all it’s inhabitants are just visitors from the real world and was also created by the same people/culture the main characters are from