The National Organization for Marriage, the group leading what it has acknowledged is an uphill fight to stop same sex marriage, charged giant cereal maker General Mills, a mainstay of many a family breakfast table, with trying to destroy heterosexual marriage.

On Thursday, the group accused General Mills CEO of declaring a “war on marriage” with its own customers because General Mills CEO Ken Powell spoke at an LGBT pride event saying the company opposes an amendment to ban same sex marriage in Minnesota, where it is headquartered.

Minnesotans will vote on a ballot measure in November that would amend their state constitution to ban same sex marriage.

The cereal maker issued a statement saying, “We do not believe the proposed constitutional amendment is in the best interests of our employees or our state economy — and as a Minnesota-based company we oppose it.”

Brian Brown, president of the National Organization for Marriage, said, “General Mills makes billions marketing cereal to parents of young children. It has now effectively declared a war on marriage with its own customers when it tells the country that it is opposed to preserving traditional marriage.”

Brown predicted that the General Mills position “will go down as one of the dumbest corporate PR stunts of all time. It’s ludicrous for a big corporation to intentionally inject themselves into a divisive social issue like gay marriage. It’s particularly dumb for a corporation that makes billions selling cereal to the very people they just opposed.”

In a sign of how tough Brown’s pitch has become, his group had asked Minnesota companies only to remain neutral on the issue.

General Mills is frequently praised for its worker friendly policies. Ken Charles, the company’s vice president of global diversity and inclusion, wrote on the company’s blog Thursday, “Obviously, there are strongly held views on both sides. We acknowledge those views, including those on religious grounds. We respect and defend the right of others to disagree. But we truly value diversity and inclusion — and that makes our choice clear.”

Same-sex marriage opponents are currently boycotting coffee titan Starbucks, based in Seattle, because Starbucks opposes a similar amendment also on the ballot in Washington state. A “Thank You Starbucks” web campaign has received 650,109 signers, while the National Organization for Marriage’s “Dump Starbucks” campaign has gotten 44,387 supporters.