from the article:
"These attacks are most likely coming from vested polluter interests (including some ALEC members who are actual regulated monopolies) that want to protect their profits."
If I understand correctly, a "vested polluter interest" is not an individual but a legal entity/corporation. To refer to such a member entity as a "who", particularly given the subject of the article, is a tacit endorsement of Citizens United, the grease on which ALEC has slid into its current position.
It reminds me of the carefully groomed economist's trope of wanting "to grow the economy". This phrasing has always struck me as something akin to astro turf claiming to be a naturally, millennially generated climaxed prairie land with full flora and fauna.