I don't see how this makes Facebook worse than other corporations. Isn't trying to influence the goverment (and probably partially succeeding in it) the norm?
The Supreme Court has declared that corporations have many of the same rights as individuals. We fleshly individuals, however, do not have the same power as mega-corporations, nor does our 'free speech' have the same same power as 'free speech' promulgated/backed by a $100B corporation, nor will my campaign contribution have the influence as a corporation's (left-wing, right-wing, whatever). Is it inappropriate to be worried?
Assuming you are referring to Citizens United, that is not what the court decided.
The court decided that individuals have the right to both peaceably assembly and freedom of speech. In particular, it's not an XOR - the government can't say "because you have peaceably assembled (in corporate or other form), you can no longer speak freely."
Citizens United was solely about the right of individuals to speak, and to use their property (corporations) for speech, as well as the right of other individuals to hear all ideas.