Sports Entertainment Network, the radio station's parent company, said Casey's views in the column were inconsistent with the company's values of equality, respect and inclusiveness among all sports and athletes.
The tone and language used in the piece were highly disrespectful to New Zealand's female sports athletes, it said.
Casey said the move to terminate his contract was unexpected.
"Obviously, it's an opinion piece and it's designed to create debate and discussion. For sure, [I] could've ... articulated it better."
"I wasn't naive enough to think that it wasn't going to ruffle any feathers but at the end of the day, it is an opinion piece and not everyone is going to agree with it."
"From my point of view, it was an opinion piece about the economics of rugby in New Zealand, it wasn't 'let's have a potshot at women's rugby'."
In the piece, Casey took aim at Farah Palmer Cup player Alice Soper for how she had put pressure on New Zealand Rugby (NZR) to get more game time for the Black Ferns.
"Vocal commentator Alice Soper who is a member of the Wellington FPC team went as far as to publicly spray NZR about doing everything possible to ensure the All Blacks play, but not the Black Ferns," the piece said.
"She honestly believed during such horrific [Covid-19] economic times, the NZR shouldn't have prioritised the biggest money-spinners in the game, the ones that pay for the competition she plays in ..."
Speaking to Newstalk ZB's Heather du Plessis-Allan, Soper said New Zealand Rugby had already struggled to make money before Covid-19 and women's rugby hasn't made anything worse.