It's a bit more than talk.while there is talk of them being a new company
In the eyes of their fans (and most non-fans as well) they still have all of the history of the old Rangers team.they most certainly are not a new club.
However, from a legal point of view, they dont have any history. They are a new club who have not played a single game and they have never been part of the league setup. They have no more right (arguably less) to join the league as any of the other clubs who want to join.
Obviously, it would be ridiculous for Rangers not to be involved in the SFL at all and i'm sure it will not be allowed to happen, but you can't say that the complaints from Spartans is "nonsense". They have a perfectly valid argument for taking up any vacant position in the league system left by the exit of Rangers.