Just because you're asked to input your information yourself doesn't mean that ParkRun don't mind you putting in incorrect information. You're asked to declare your own information, not make it up.
I am asked to 'self-ID' my date of birth dozens of times a year. None of them make me also scan my birth certificate. That doesn't mean its on to make one up. They're asking people to enter the truth. Would ParkRun support 20 year olds entering the junior ParkRun?
ParkRun need to ask participants for their sex. Their actual sex. And their actual date of birth. Yes, some men will lie and put female, but at least then, everyone is clear that they are cheating.
The falsehood that the records don't matter and its not a race is completely disingenuous, and another lie, because of that were true they wouldn't publish the times, position, position by (sex) category, grading based on your age and sex, course records for male and female every week within an hour of the 'not-a-race'. Those matter, and ParkRun know they matter. Women are, as always, the ones who lose out.
And 'Lauren Jeska' isn't the only man holding women's ParkRun records in the UK.