Because from a story perspective, that building isn’t supposed to exist. They’re not trying to draw attention to the fact that you enter one building, get in a car, and then launch into another building a few feet away. The idea is that you are launched into space.Why? When something is that visible and they cant hide it, why not make it look like a building from guardians or theme it in some way at the very least. Make it a space port, or make it part of the u of e building and continue the design.
Disney does not want that building associated with GotG:CR in any way. That’s why guests will not enter it from the outside or exit from it to the outside. From a thematic perspective, the former UoE building is the one and only Guardians building.