If I understand Facebook, you "like" someone in order to get news from them. Now that Romney is not running any more, there is no reason for people get more news from him. People "unliking" Romney is to be expected. Do people actually think Facebook "liking" necessarily means an emotionally positive connection and "unliking" a emotionally negative connection?
As long as he's no longer posting a hundred times a day about how he's going to restore American greatness, there's no reason to "unlike" him. You don't even notice that he's among your "likes." So if people are unliking him, that would indeed suggest an emotionally negative connection. First there are all the people who, such as me, "liked" his page just so they could troll the morons who support him. They're probably deliking him right now. After that you might have some Teabillies who were never that enamored of him to begin with.