Corporate personhood has ailed our political process for far too long. Particularly after the Supreme Court's "Citizens United" decision, which essentially allows corporations to funnel unlimited money into political advertising, our populace and government are becoming beholden to corporate interests.
As people become increasingly dependent on non-print media for information, a boom of corporate-aligned political ads over the TV and Internet can easily distort and skew perceptions about proposed laws and candidates. Corporations have huge amounts of money and financial resources to create and keep these ads running - far more than individuals - so they can essentially buy much more influence.
Corporations are not people and should thus not be protected by the Constitution as such.