> I don't know the answer to get rid of all corruption, but how is it that ISP's were able to give money to politicians who voted against net neutrality?

There are four things that are often described by activists and the media as donations by corporations (sometimes combined, sometimes just one or the other—the first and third seem to be the most common where dollar figures are given, because they are most readily available), in roughly decreasing order of the degree to which such descriptions are misleading:

(1) donations by employees of the corporation (regular individual donors with reportable donations must disclose their employer, and often donations by employees of a firm or industry are described as donations by the firm or industry.)

(2) Donations to “leadership organizations” directed by candidates (this is misleading when described as a campaign donation to the candidate, because such organizations are conduits that allow the candidate to promote other candidates), and

(3) Donations to SuperPACs that align to some extent with a particular candidate. (This is a wobbler in terms of how misleading g it is, because some superPACs are essentially focussed on a single candidate, and some are more general.)

(4) Donations from a corporate “separate segregated fund” (this money doesn't actually come from the corporation as such—it is separately solicited from managers and shareholders—but is directed by it.)

The particular article you refer to expressly combines the first two categories.

So, to completely ban the contributions identified in that article, you'd have to prohibit anyone with a job from contributing to a political campaign, and to eliminate everything commonly portrayed as corporate contributions, you'd have to also outlaw independent expenditures (which are what SuperPACs do) on political advocacy.