However, it seems that McD tried to use their trade mark to prevent Supermac to sell other burgers with similar (but not the same) name.
This ruling essentially says: "Big Mac" is only protected for selling beef sandwiches, and "Supermac" is distinct enough that if you use it to sell chicken sandwiches, that's fine.
In the process, the court ruled that McD didn't actually use the "Big Mac" trademark for anything except beef hamburgers, so it's no longer a protected term for adjacent things. You could call your restaurant "Big Mac", and it wouldn't be a trademark violation, because your restaurant is not a beef hamburger.