But politics makes strange bedfellows, and Mr Kogan has come to Mr Harvey's defence following criticism from a single-issue pressure group.
A group called Markets for Change recently issued a report claiming that Harvey Norman is "fuelling the destruction of our native forests" by selling furniture that was made in China from timber originating in Australian natural forests as opposed to plantations.
Although the report claims other retailers - including Freedom Furniture, Forty Winks and Snooze - buy products from the same importers and manufacturers, Harvey Norman was singled out: "As Australia's largest retailer of furniture and electronics in Australia, Harvey Norman, its management and its shareholders have a special responsibility to source products in an environmentally responsible way."
The leadership of Markets for Change almost entirely comprises people who have previously worked with or for Greenpeace or the Wilderness Society.
So what did Mr Kogan have to say in Mr Harvey's defence? See page 2.