The reason I mention that the vast majority of people disagree with the fairness of transgender females competing against biological females, is as a counterpoint to the Transgender characterisation of dissenting voices as isolated and bigoted opinions which go against the collective grain.
A few very vocal and shrill voices on Twitter come together to portray the illusion that their propaganda is now a generally accepted public perception. In reality, this is not the case. If you read the feedback on these stories in the comments sections of, for example The Independent or The Times - well over ninety percent of hundreds of comments do not agree with the opinions of proselytisers like Rachael Mckinnon.
And these are polite, well thought out and reasoned opinions - not the sort of trolling negativity you might get at Lets Run or most of the lowbrow rags that pass for newspapers these days.
There hasn't hitherto been much need for research into the biological advantages Trans Women athletes have over biological women and thus stating that, "there is no evidence that trans women have an unfair advantage in sports after proper transitioning" is misleading as there is very little independent scientific evidence on the subject in the first place. The more that this situation becomes a major headache for sports administrators, the more likely thorough scientific research into the problem will be undertaken.
For most of us, it seems pretty "obvious" that Transgender women have a competitive advantage over biological women. However, if it can be "proven" that no such advantage exists, then of course the matter will be finally settled and those opinions will change.
This isn't the situation that Rachael McKinnon asserts already exists at the moment though, as having "no evidence" of an advantage is not the same thing as having evidence that proves there is no advantage.