I don't understand why it needs to be "given" back. Haas offered the Giants the San Jose area to the Giants. (Even though it presumably would help him if the A's were the only team in the Bay Area) But the Giants obviously didn't move to San Jose, in fact, they moved farther away.)
So, in what way would the Giants still own the San Jose rights? It was unjust enrichment? They took something from Haas without consideration.
MLB (Selig) ruled that San Jose is now Giants territory. Although I find it ridiculous, it kept the A’s from building a stadium there. Considering that San Jose is California’s 3rd largest city in terms of population, the A’s would have flourished there.