Firstly, SPH is a listed company. They have to answer to their shareholders and they include people from all races. In fact, on Chn i news, there was a guy, a shareholder who was very fiery tells SPH to shut down tv station because it is losing money. That guy if i remember correctly also says why you need two chinese stations .. a bit racist leh. (that guy is non chinese).
So they probably thought about that, and since the big big boss said it before, they have to bow and obey instructions
Mediaworks also spent too much money buying TVB dramas which can't even beat local productions. Someone must have got blamed like throwing money and give it to HK So they decided to call it quits. Immediately after the news was announced, the SPH shares rose.