The San Francisco Planning Commission postponed a decision Thursday on whether a Whole Foods 365 store will be allowed to open at Polk and Jackson streets, but in it was a desire for housing — not opposition to chain stores — that drove the discussion.

After three hours of spirited public comment and debate, the Planning Commission gave the property owner and Whole Foods an additional 90 days to consider whether some housing units could be built above the proposed 20,000-square-foot Whole Foods 365, which the company bills as a more affordable alternative to its famously costly grocery stores.

The debate was defined by three groups: Residents of Nob Hill and Russian Hill, who by and large were strongly in favor of the store; local business owners and Middle Polk neighbors who opposed it; and housing activists who argued that converting the store to a grocery would be a missed opportunity to help ease the housing crisis by building residential units over ground-floor retail.

Commission President Rich Hillis said he would generally not oppose opening a Whole Foods or any other grocery store, which many urban neighborhoods spend years trying to attract.

But the developer’s decision to forgo a mixed-use project in favor of a straight reuse of the old Lombardi Sporting Goods store at 1600 Jackson St. didn’t feel right, Hillis said. He pointed to successful housing over Whole Foods developments in Upper Market and on Potrero Hill.

“The overwhelming majority of residents are in favor of this project,” he said. “If there were seven or eight stories of housing proposed above, we wouldn’t be here. Unfortunately, that is not what is before us.”

Opposition to the proposal included generally pro-development groups like the Housing Action Coalition, which argued the site was ideal for residential development. Opponents also said a Whole Foods 365 would decimate nearby businesses like the Jug Shop and Cheese Plus and that it would lead to gridlock on Polk Street. And many pointed out that Whole Foods is now owned by Amazon, considered by some to be a ruthless destroyer of local businesses.

Rick Karp, president of the San Francisco’s Cole Hardware stores, said that Amazon’s acquisition of Whole Foods “changed the nature of the game.”

“Amazon is currently basically raping and pillaging retail in San Francisco,” Karp said. “They specialize in putting local businesses out of business. We know what they have done to the bookstore business. They will do the same to wine and cheese and much more.”

But neighborhood residents said a Whole Foods could revive a struggling Polk Street corridor. They pointed to a dozen storefront vacancies and said the block at Jackson and Polk streets has been a magnet for homeless camps.

Groups against the development included the Middle Polk Neighborhood Association, the Polk District Merchants Association, Folks for Polk and the Pacific Avenue Neighborhood Association. On the other side, all of the condominium associations surrounding the project — representing 284 units — endorsed the store.

Carol Ann Rogers of the Russian Hill Neighborhood Association said the neighborhood needs a full-service grocer and that the proposal is the “most reasonable, feasible and timely way to serve this need.”

“We believe that more and more housing cannot be built without providing basic services that current and future residents need,” Rogers said.

While the Planning Commission directed the developer to explore adding housing, a new, ground-up project would not allow a grocery store because zoning laws on Polk Street prohibit a retail space of more than 4,000 square feet. Instead the property owner and developer said they would look at housing on the existing second floor of the building, which would probably accommodate fewer than 20 units.

J.K. Dineen is a San Francisco Chronicle staff writer. Email: jdineen@sfchronicle.com Twitter: @sfjkdineen