In all fairness to Hayworth, the author needs to tell us: O.K., which one of those things did McCain NOT support.
With regard to the author's concerns about lobbyists (petitioning your government, via collective action through your associations) and their campaign contributions go;
if it is a corruption simply to "lobby" for particular legislation AND also financially support the legislators who support your cause, then unions have the most, most often and deepest corrupt lobbying association with Congress, and they don't even have to call themselves "lobbyists" to achieve it.
People hate lobbyists mostly because of how the entire area of "lobbyists" is portrayed by the media, and, in that regard, how it is always portrayed as a loss for the "public interest" when a piece of legislation has been formed in a manner some "lobbyists" are happy with.
Often, the resulting negative connotation about "lobbyists" results from the media supported public ignorance of the facts, of what the legislative alternatives were (the ones the media said were good), of what would have been the actual "unintended consequences" of those alternatives, the economic and legal principals involved, and how the populist desire to "take it out on the big guys" often is against the real "public interest" in the long run - what corporations "pay" in "taxes" is passed on in what they charge in prices; and usually THOSE results (cascading) affect most those of us with the least. If one wants to consider REAL corporation, via "lobbying" then consider how Mister Murtha has purchased his seat in Congress with campaign funds supplied overwhelmingly with money from a few defense contractors to whom Murtha - via his role on the House defense appropriations committee - has supplied perpetual, one vendor, monopoly defense supply contracts.
Actually, I don't think he has to, either to be fair or to defend his point. The whole "elect JD" thing is based on the idea that McCain is the worst of the worst and if he loses the primary we'll still keep the seat for the GOP. Since JD's boosters act like he's a conservative white knight and the author's point is that JD is flawed rather than that McCain is good, McCain's record is largely irrelevant. If he had a rock solid conservative voting record we wouldn't be having this conversation.