A chorus of Internet service providers and supportive policy groups are crying foul after the Wall Street Journal reported that Netflix Inc. has been slowing down, or “throttling,” its streaming video speed to subscribers who use AT&T and Verizon Communications wireless services.

The ISPs are up in arms because Netflix has been a staunch champion of the Federal Communications Commission’s net neutrality rules, which prevent the ISPs themselves from slowing traffic moving across their networks.

It turns out, according to the report, that the streaming video giant has for more than five years been slowing those subscribers’ video traffic to 600 kilobits/second broadband speeds—just barely above the minimum 500 kbps speed Netflix says customers need to use the service.

In a March 24 blog post, Netflix spokeswoman Anne Marie Squeo said that speed was the “default bitrate for viewing over mobile networks,” and that Netflix slows mobile video traffic to help consumers avoid going over their monthly data caps, which could result in hefty additional fees. The company declined to comment aside from the blog post.

ISPs could receive a hefty fine under the net neutrality rules for similar practices, but Netflix faces no such danger, at least not for the throttling itself. The net neutrality rules only apply to ISPs and those who control access to the Internet, not to companies that operate over it, like Netflix or Google Inc.

Netflix’s practice does, however, add a new wrinkle to the debate over how, who and when federal authorities should regulate in the Internet ecosystem.

Netflix—whose traffic alone accounts for 37 percent of wireline Internet use in North America in 2015, according to Sandvine, an Internet traffic management firm—was one of the lead proponents of stricter regulations for ISPs under Title II of the Communications Act, including a bright-line prohibition on throttling online traffic by broadband providers, due to what Title II advocates said is ISPs’ unique gatekeeper status for Internet access.

Some ISPs and Title II opponents have countered that the practices banned by the FCC could be beneficial to consumers, a fact some were quick to point out in response to the Wall Street Journal report.

“Netflix fought hard during the open Internet proceeding to ensure that broadband providers could not engage in this same behavior that would benefit the same customers in the same way,” said Doug Brake, a telecom policy analyst with the Information Technology and Innovation Foundation, a Washington think tank.

“Most content providers already build adaptive bitrate algorithms into their streaming service, allowing the video to adjust its resolution to the network conditions. Adapting streams with a hard cap on data rates for resource-constrained mobile networks is not much different,” Brake said.

Even some of the groups criticizing Netflix for the hypocrisy of the policy advocacy said the company’s mobile video throttling wasn’t inherently wrong. They did, however, question the company for not disclosing the practice to its subscribers.

And the lack of disclosure, rather than the throttling itself, could be what gets the video Netflix in trouble with the feds— namely, the Federal Trade Commission.