Christian advocacy organisation the American Family Association posted a Kellogg's ad on their Facebook page that has angered many Christians.
The ad was taken from the Atlanta Gay Pride festival's Pride Guide, and Kellogg's was a proud sponsor.
"Wear your stripes with pride," the headline read, using the colours of the rainbow for the word "pride."
"At Kellogg, we're an evolving culture that respects and accepts employees' sexual orientation, gender identity and gender expression so that all employees can be authentic and fully engaged," the ad explained.
The advertisement also includes a photo of Frosted Flakes mascot Tony the Tiger, a logo for Kellogg's LGBT-focused employee resource group, K-Pride & Allies, and a sticker showing that Kellogg was selected as one of the Best Places to Work for LGBT Equality in 2014 by the Human Rights Campaign.
Some Facebook commenters did not realise that Kellogg was an outspoken supporter of LGBT causes, and expressed frustration and disappointment with the news.
"I guess they just lost our business...." a Pennsylvania woman wrote.
"The only way to hit these companies is where their hearts are- greed!!! money we must band together and stop giving them our money!!!" Kim Philpot said. "Do you see them sponsoring any Heterosexual activities or Christian Activities?"
Others exposed the irony of discussing the issue on Facebook – a company that also supports LGBT causes.
"Funny how people use Facebook everyday unaware of the company is a huge gay rights supporter!" Edvin Duke wrote. "Christians should dissappear [sic] from Facebook too!"
The W.K. Kellogg Foundation is one of the biggest philanthropic organisations in the country, and supports a variety of causes around the world – a fact that several Facebook users pointed out.
"Actually Kellog's provides MILLIONS of dollars to the Christian community via their foundation," Scott Wooledge explained. "Do not let that interfere with your persecution complex however," he added.
The use of Tony the Tiger, a cartoon mascot designed to attract children, was the biggest problem for some commenters.
"Why? Why use a cartoon tiger?" Jessica Kelly asked. "Camel got heat for 'marketing cigarettes to children' because of their cartoon camel. Is it just me, or is Tony now marketing a sexual lifestyle to children?
"I don't care if that tiger, or any of Kellogs' [sic] employees are gay or straight or short or tall or black or white. I really don't care. But their use of a cartoon tiger to MARKET a sexual lifestyle to children is atrocious."