What I was getting at was that it's no shock that the production company decided to change the title to Sicario 2, because despite what Sheridan said, even if it was just called Soldado, everybody would still consider it a sequel to Sicario. The main characters in Soldado are two of the main characters from Sicario, literally the only one missing is Emily Blunt. It's not like this is some big unprecedented thing in movies. Look at for instance the Mad Max films, the only connective tissue between any of them is the fact that there's a guy called Max Rockatansky in the lead role, but everybody still considers The Road Warrior to be a sequel to Mad Max, Beyond Thunderdome a sequel to The Road Warrior and Fury Road the fourth film in the franchise.
Now if Soldado's original script didn't feature Brolin and Del Toro's characters and that it was the studio's decision to change the film into a sequel to Sicario (which has happened in the past with for instance 10 Cloverfield Lane and Die Hard With a Vengeance), then I would be 100% with you that the studio fucked this by tacking on the Sicario name. However, that was not the case and from the studio's perspective I fully understand the decision to give it the Sicario name, since everybody would've seen it as a Sicario sequel anyway, so why not try to cash in?