The complainant said the article breached Clause 12 as she considered the claim that she was “a man who claim[ed] to be a woman” to be discriminatory as she legally changed her gender in 2018. The complainant considered she was deliberately misgendered with the intention being to offend her.
IPSO considered referring to the complainant as a man “claiming” to be a woman was personally belittling and demeaning toward the complainant, in a way that was both pejorative and prejudicial to her gender identity, and was not justified by the columnist’s right to express their views on the broader issues of sex and gender identity. As such, there was a breach of Clause 12 (i) on this point.
Clause 12
i) The press must avoid prejudicial or pejorative reference to an individual's, race, colour, religion, sex, gender identity, sexual orientation or to any physical or mental illness or disability.
Clause 12 of the Editors’ Code of Practice deals with discrimination. It says the press must avoid prejudicial or pejorative reference to a person’s race, colour, religion, sex, gender identity, sexual orientation or to any physical or mental illness or disability. It also states that these details should not be included in a story unless they are relevant.
In general, Clause 12 complaints can only be taken forward from the party directly affected – because the complaint might involve personal and sensitive information about a person, or we might not be able to investigate the complaint properly without their input. In certain cases, where there is a sufficient public interest, IPSO is also able to take complaints from representative groups affected by the alleged breach.
https://www.ipso.co.uk/what-we-do/monitoring/clause-12-monitoring/
Looks like it's the word 'claiming' that's the problem.
Ridiculous.