One thing that boosts sales is that the show has many ironic fans as well as its legions of genuine enthusiasts, and merchandisers are making products for both groups, said Martin Brochstein, SVP at International Licensing Industry Merchandisers Association.
"'Duck Dynasty' has managed to hit a sweet spot in pop culture," Brochstein said.
(Read more: 'Duck Dynasty' wine: Reds from reality TV's famous rednecks)
Wal-Mart Stores has benefited more than any other retailer, with "Duck Dynasty"-related products in about 15 of its departments, Brochstein said. Of course the show sets up the Robertsons to add products to their own Duck Commander business, including a new line of rifles and hunting supplies.
Will Robertson's offensive comments have any impact on merchandise sales?
The timing of the controversy—right around the big holiday retail season—was inopportune, but it's too soon to say if the controversy will have any long-term impact, Brochstein said.
Cracker Barrel said it was going to pull "Duck Dynasty" merchandise, then made an about-face, saying it would continue to sell some products. Others haven't backed off, despite despite opposition from GLAAD, the Human Rights campaign and the NAACP.
Brochstein says it's pushing consumers to make "Duck Dynasty" purchases a personal vote on the Robertsons' beliefs. "It now makes it a conscious cultural choice." And in the meantime, while we wait to see if retail sales wane, the show is expected to continue to draw record viewers—its last season premiere drew nearly 12 million viewers, the most-watched cable non-fiction show ever.