Not everyone agrees that the UK's gender recognition certificates(GRCs) allowing adults to change their legal sex have "benign natures" like you say - and it's definitely not true that "until recently, they [GRCs] have been uncontroversial."
It's also not true that GRCs do not provide adult males who hold them with a "pass to enter so called women's spaces unchecked." At least not according to the way that GRCs and the law that created them, the Gender Recognition Act of 2004, have been interpreted and applied to date by UK government ministries, departments, councils, state-run schools, NHS trusts and hospitals, private business establishments, arts institutions like theaters and museums, and providers of services originally founded by women to assist female victims of male sexual assault and male domestic and intimate partner violence.
For example, in England, Wales and Scotland, male convicted criminals who have obtained a GRC prior to conviction are automatically sent to women's prisons, even if they only applied for their GRCs after being arrested and charged. Moreover, male convicts can (and do) obtain GRCs whilst they are serving time in men's prisons for past convictions - and once a GRC is granted, they automatically have the right to seek immediate transfer to a women's prison.
For example, Lauren Jeska - the male runner convicted in 2016 of premeditated attempted murder for trying to kill UK Athletics staff in a violent, frenzied stabbing attack that left three big, strong men injured and one nearly dead which I detailed in my earlier post - is serving Jeska's sentence in a women's prison.
Males with GRCs - and in recent years, many without GRCs too - are being placed in women's prisons in England, Wales and Scotland even if the crimes they are currently serving time for, or were convicted of in the past, include crimes of sexual violence against women, including rape.
This creates huge safety risks for female inmates of women's prisons, and for female prison staff as well, because an unusually high proportion of adult males in UK prisons who "identify as" women are convicted sex criminals whose victims were/are women and girls (the female kind).
The figures vary from one year to the next, but according to the UK's Ministry of Justice, in recent years anywhere between 44% and 58% of the adult males in prison in England and Wales who claim to "identify as" women have convictions for sex crimes against women and/or children. By comparison, a much smaller proportion - about 16% - of the rest of the grown men in prison in E&W in any given year of late are convicted sex offenders.
Moreover, the crimes committed by males with GRCs - including rape, which in English law is a crime that by definition involves sexual penetration with a penis - are automatically recorded by police and the CPS as crimes committed by women. This has led to many police forces also recording crimes committed by men as crimes committed by women so long as the men simply say they "self ID" as women.
Recording and counting male crimes as female crimes has led to marked skewing of UK crime statistics in recent years. When crimes committed by men are recorded as crimes committed by women, it not only hides the extent and nature of male violence, it also unfairly makes women appear to be the culprits of male misdeeds - and it makes women appear to have considerably higher rates of criminality than we actually have.
The practice of recording men's crimes as crimes committed by women has also led to a noticeable rise in sex crimes supposedly carried out by women in the UK in recent years. These include many kinds of sex crimes that female people don't customarily commit - such as rape, possession and distribution of photographic and video imagery showing children being sexually abused, voyeurism, sexual spy camming, upskirting, sexual stalking and menacing - along with crimes in which the perpetrators are said to have used or exposed "her penis" such as flashing and forced touching of the perps' so-called "manhood."