An amenity=university area represents a single university campus. The area in question is Main Campus.

If we combine Main Campus and South Campus into a single geometry, we lose the ability to indicate that they have different addresses and different Wikidata IDs, or that Main Campus is a static historic landmark while South Campus is not. [1]

SJSU considers Hammer Theatre, the International House, the Child Development Center, the Mineta Transportation, and the hangar at Reid–Hillview to all be off-campus facilities. [2] However, their map of off-campus facilities does depict the North Parking Garage as part of Main Campus.

[1] https://ohp.parks.ca.gov/ListedResources/Detail/417
[2] https://www.sjsu.edu/map/off-campus.php