Popular online dating website OkCupid is urging its users to boycott Mozilla’s Firefox browser after the company’s new CEO was linked to an anti-LGBT campaign, but Mozilla says it fully supports equality.

Firefox users who have visited OkCupid.com in recent days would have received a pop-up letter on their screen urging them to “consider different software for accessing OkCupid.”

“Hello there Mozilla Firefox user. Pardon this interruption of your OkCupid experience,” the letter starts. “Mozilla’s new CEO, Brendan Eich, is an opponent of equal rights for gay couples. We would therefore prefer that our users not use Mozilla software to access OkCupid.”

Although it’s not addressed in the letter, OkCupid is referring to controversy over Eich’s apparent support of California’s controversial Proposition 8, a now struck-down constitutional amendment that blocked same-sex marriage in 2008. According to news reports, Eich, who became CEO of Mozilla in late March, donated money to the initiative.

OkCupid, which boasts seven million active users and is owned by Internet giant InterActiveCorp, says in the letter that “politics is not normally the business” of a website, but then goes on to explain why they are taking a stand

“We’ve devoted the last ten years to bringing people – all people – together,” the letter states. “If individuals like Mr. Eich had their way, then roughly 8% of the relationships we’ve worked so hard to bring about would be illegal. Equality for gay relationships is personally important to many of us here at OkCupid.”

However, in a statement on its site, Mozilla said it’s “deeply committed” to honouring diversity in sexual orientation within the company, noting that they offer the same level of health benefits to “domestic partners” as they do to married couples across the United States, even in states where it is not mandated. The statement also links to a blog post Eich wrote on inclusiveness, as well as a statement from executive chairwoman Mitchell Baker.

In Eich’s blog post, he acknowledged the “concerns about my commitment to fostering equality and welcome for LGBT individuals at Mozilla.”

Eich wrote he is committed to equality and working with LGBT communities and allies to “listen and learn what does and doesn’t make Mozilla supportive and welcoming.”

Although there is no mention of Prop 8, Eich expresses regret in the blog post.

“I know some will be skeptical about this, and that words alone will not change anything. I can only ask for your support to have the time to “show, not tell”; and in the meantime express my sorrow at having caused pain,” Eich wrote.