The media mogul appeared Thursday at a parliamentary committee hearing into why the CBC is fighting access-to-information laws in the courts.
The corporation says it has been swamped with hundreds of information requests, mainly from Quebecor's many media outlets, and suspects an orchestrated campaign to damage it.
But Peladeau denies that the quest for information is anything more than independent journalists doing their work.
"Despite what some may think, in other words, that we are waging a war against CBC-Radio Canada, we believe that these requests are not only legal but also legitimate and in the public interest and in keeping with the act," Peladeau told the access-to-information committee.
Still, he went on to threaten legal action against the CBC for putting out a statement earlier this week about Peladeau's own lack of accountability in receiving public funding.
He also lashed out at the corporation for pulling all its advertising from Quebecor media and admitted under questioning that he had written the prime minister to complain.
And he chronicled how CBC had withdrawn advertising from his Journal de Montreal during a labour dispute. CBC had wanted to run ads in the sister paper in Quebec City instead, but Quebecor refused.
The two companies compete head-to-head in Quebec for television viewers. Quebecor's Sun Media division frequently publishes criticism of the CBC and has urged an end to its public funding.
Opposition critics suspect Quebecor has allied itself with the federal Conservatives, who recently surveyed party members on whether the CBC provides good value for the taxpayer.
They are now eyeing budget cuts.
Indeed, Conservative MP Dean Del Maestro praised Sun Media's journalists for being "courageous" in taking on the powerful CBC through access-to-information requests.
"The CBC is not a small entity in the media business in Canada and I think if you're going to come out and challenge them, that takes some courage as a media player in Canada," he explained to reporters after the committee hearing.
"It's a courage of conviction."
Peladeau argued that no other media organization in Canada is prepared to scrutinize spending at the CBC because almost every other organization is in some way compromised.
"Unfortunately the reality is that currently Sun Media is the only press organization that is sufficiently at arms'-length and independent to be able to put those questions to the public broadcaster, because so many of our competitors are involved with CBC-Radio Canada," he said, listing several examples.
"Between their strategic partnership, their advertising budget and their direct payments to journalists in other media organizations, CBC-Radio Canada has somehow managed to quiet dissenting voices in most outlets. Everywhere, that is, to the exception of Sun Media."
A spokesman for CBC said the corporation had nothing to add on Thursday, beyond the statement published Wednesday night listing federal support received by Quebecor, as well as CBC's efforts to disclose more information.
The committee hearings are meant to look at a section of the Access to Information Act which exempts CBC from having to divulge material involving its journalistic, creative or programming activities.
Peladeau and others accuse the CBC of using the section to hide all sorts of material and stymie scrutiny into the spending of taxpayers' money. They argue that CBC should allow the federal information commissioner to decide which information can be exempted, instead of having to battle in court.
CBC officials argue that they have been transparent about many things and have improved their response to access-to-information requests. They say only a judge should be able to look at records that have been held back.
But lawyer and access expert Michel Drapeau, who is doing work for Quebecor, says that kind of response is "condescending."
He told the committee that the CBC is engaged in a "blatant" exercise to delay and impede the release of information to which the public has a right.