Well considering that particular post and specifically “Mumsnet is the most homophobic and transphobic website I've ever been on, and Mumsnet themselves actively allow it”, I would say that the poster might have a habit of posting outside the talk guidelines
I might also suggest they have their own personal definition of homophobia and transphobia. Definitions that they except others to comply with. They seem upset that others reject those personal definitions and use ones that are considered reasonable by the majority of the population and indeed, the government that set the laws.
They seem upset that an organisation that provides a service can set the guidelines that those using the service need to abide by. And I am all for people influencing the organisation to make changes where needed, so good luck to them for trying to get Justine to change her policies.