Mumsnet’s call for reform would have allowed for spaces to be reserved for biological women.
Ms Roberts said the forum had also made “repeated attempts to explain our position – as a platform committed to amplifying women’s voices” but Ocado had “refused to speak to us”.
In a post on X, Ocado said the comments were “not representative of us as a company” and that they were made by a “temporary contractor” who has since left.
“We apologise unreservedly to Mumsnet,” the online grocery site added.
Ms Roberts wrote her post in a discussion on the forum about the Supreme Court ruling. In the post, she congratulated those on the website “who played a part in securing what I think most would agree is much-needed clarity in the Equality Act”.
The ruling was on a case campaign group For Women Scotland brought against the Scottish government, arguing that sex-based protections should only apply to people that are born female.
Judge Lord Hodge said the ruling should not be seen as a triumph of one side over the other, and stressed that the law still gives protection against discrimination to transgender people.