Companies/rich individuals donate to both political parties all the time. It's basically a cost of doing business and allows them to lobby and have "friends" in power no matter who wins. This is not to say this isn't a problem--it certainly is--but Facebook is far from unique in doing this.
Most of these big donors play all sides. Of coursee it will weigh more to the side that's in power currently. The only loser is the common people.