In the ongoing fight over proposed rules that would institute net neutrality, a major proponent of the policy is taking fresh heat from critics. Google, arguably the world’s biggest name in tech, a major source of campaign donations to President Barack Obama, and one of the most prominent advocates of an “open internet,” is taking heat for alleged hypocrisy and rent seeking.

The criticism comes as the company continues to advocate for the Federal Communications Commission (FCC) to impose net neutrality rules that would target internet service providers (ISPs) while opposing so-called “search neutrality” that would impact both the company and its revenues in a manner that observers of the debate say could be particularly adverse to Google.

Last week, in a post on the official Google blog, the company’s senior vice president for product management, Jonathan Rosenberg, wrote that while Google’s “goal is to keep the Internet open,” it opposes the concept of “openness” where it would apply to its own search and ad products.

Ironically, the rationale behind Google’s opposition to “open internet” policy of this sort sounds remarkably similar to the rationale expressed by ISPs–which Google and other “open internet” advocates have targeted as the enemy in the current fight regarding FCC rules–for opposing net neutrality. According to Rosenberg, opening up Google’s code “would actually hurt users” and result in “reduced quality” for those who rely on the service in question.

That is an end result that net neutrality opponents say could equally well be assured by instituting that specific policy, though they allege that a key difference is that net-only neutrality would help, not hurt, Google, from a financial perspective. Broader openness, by contrast, would strike a major blow to Google–and open internet advocates and major voices in the tech sphere are now calling the company out for dressing up a public policy stance that appears to driven by a pure profit motive as philosophically principled and heartfelt.

In a recent post at Boing Boing, blogger Rob Beschizza comments on how odd it is “that of all the products Google would be forced to keep proprietary by its commitment to an open internet, it just happens to be the ones that make it all of its money.”

At top tech blog Tech Crunch, meanwhile, writer Erick Schonfeld posted an item titled “For Google, The Meaning Of Open Is When It’s Convenient For Them.” In it, Schonfeld responds to Rosenberg’s assertion that openness in the realm of search and ad products would “hurt users” saying:

Maybe, but it is more likely it would hurt Google… really nobody should begrudge them the right to keep products they’ve spent a lot of time, energy, and money building to themselves. But don’t give us this song and dance about how everything should be open and how Google is the opennest company in the world…. Google should just be honest and say that they think everything should be open–except for search and advertising.

In addition, an open internet advocate who alleges his firm was hurt by Google’s practices has now also called out the company for trying to argue “that discriminatory market power is somehow dangerous in the hands of a cable or telecommunications company but harmless in the hands of an overwhelmingly dominant search engine” in a New York Times op-ed.

Writes Adam Raff, a co-founder of Internet technology firm Foundem, “Google’s treatment of Foundem stifled our growth and constrained the development of our innovative search technology.” He asserts that the effect of the FCC enshrining limited openness, such as what Google wants, could be “a bleakly uniform world of Google Everything — Google Travel, Google Finance, Google Insurance, Google Real Estate, Google Telecoms and, of course, Google Books”–in short, a government-sanctioned, Google monopoly.

Observers say that is something that would undoubtedly be to Google’s significant financial advantage, but which would certainly irk anti-corporate, public interest and consumer advocate groups who together with the company have formed the core of the pro-net neutrality coalition.

“There is a growing rift” says one observer, who also noted that support for net neutrality from existing coalition members seems to be waning. That individual points to top blogger Glenn Reynolds, listed as a “Charter Member” of the pro-net neutrality Save the Internet Coalition, having recently voiced skepticism regarding efforts to regulate the internet and suggests that the coalition may be weakening.

That could be bad news for Google, but good news for opponents of the FCC’s proposed net neutrality rules. As it stands, the FCC continues to invite public comment on those rules, with a decision expected next year.