(I'm not talking unions, just about the article). That' what they're suppose to be. What we see happening all around us is government working for special interest. And as your government they have one huge advantage over corporations: They can force you to accept a single product or solution.
If I have something that I'm interested in (say, clear air), and I want the government to do something about it, when do I move from an interest to a special interest?
"Special interest," just like "big government," is nothing but a TV buzzword.
It's not as if these are political science terms of art. Imagine experts in a field choosing to use a term normally used for measurement of bulk to describe the function of a system, or wasting their time categorizing interests into "special" and "not special" based on a fixed set of criteria. Political science is deeply boring, but it's not THAT boring.
Good question! If you start hyring former and current politicians, sponsor elections, pressure your employees, try sneek in legislation, I'd say you're special interest.