I actually want the counter argument to improve.
Why?
Because a decent argument suggests there is substance to what changes are being imposed seemingly without proper due diligence.
But given the lack of that in politics in the last decade, I am cynical about that happening.
Politics has become polarised in many aspects between logical, rational, practical and ultimately enforcable ideas and laws versus this emotional screeching about how things are bad and we must change things, all opposition needs closing down through authoritarian means with this complete disregard as to how these ideas are workable in the real world.
The OP demonstrated exactly that.
These appeals to emotional are wrapped up in attempts to blackmail and shame and otherwise bully none believers who, if they do not comply, should pay the price in terms of their livelihoods and social standing. It's has echoes of a cultural purge in various institutions. Historically it looks incredibly like the 'red scare' in US politics with similar patterns of behaviour.
This is not how liberal democracy works.
Liberal democracy has to encourage engagement. The rules of that engagement are that nothing is off limits for discussion because taboo issues being overlooked don't go away. They fester. And as a result get worse until they are eventually dealt with.
The problem in framing the question of 'what is a woman' as a dog whistle is it doesn't resolve the law as it now stands. It falls apart. This leads to legal cases being launched to solve practical problems because the politicians were sleeping on the job and didn't write proper definitions which were coherent and workable. This creates legal precedents which the politicians may not actually like, but since judges have to use logic and rational and create judgements which can be explained this weakens the politicians argument.
This leads to accusations that judges are interfering in politics. This isn't true. Judges are the backstop when politicians have failed to identify and preemptively deal with issues and conflicts.
Of course this leads to a situation where the only place the debate can head is to a clarification of the Equality Act and the purpose of the Equality Act. Judges can not change the Equality Act. They can only rule based on the presumed principles and aims of the law. The law is written because it was identified that women (and other minorities) were at a disadvantage to men. The aim of the law was to provide protections to stop discrimination. The Act states both sex and those who have had gender reassignment (or are undergoing it) as two distinct but separate things. It recognises that both groups have disadvantages and thus both need protections. It also identified a conflict within this, where single sex exemptions should be applied because gender reassignment imposed negative impacts on women.
This in turn leaves us with this issue whereby the law is still fuzzy but is saying in effect transwomen are not women but can be treated as women in some situations but not all.
This in turn leads to the questions about why this was done in the first place.
And why now, there are ambitions and attempts to change this both lawfully and via unlawful means.
This makes it even more of an essential question to be asking - 'what is a women?' and 'why do women have single sex exemptions?' and 'why should we overturn the protections the law has provided?'
There is a legitimate debate to be had here about why women need to lose rights and protections they should have in principle (but are finding they often don't have in practice). All whilst transwomen (males) are saying they have the most vulnerable in society despite a lack of evidence to demonstrate this and create a coherent argument about why single sex provision should be abolished and why this action wouldnt have a massive negative impact on women - remembering that the law was written understanding of the principle that sex mattered in law because women were are a disadvantage and this was demonstrable.
The law was written on the principle of providing balance and equity in society that didn't otherwise exist because of prejudgices and inherent social power / dominance.
In saying that being a woman is indefinable you immediately remove all these protections and all the principles upon what the Equality Act was built.
A judge isn't going to be able to rule against that, without reason and argument. Saying 'be kind' to women isn't sufficient if women can demonstrate disadvantage and harms through information and data which is observable.
This throws this back to politicians. Politicians then have to decide whether to change the law or not. They can do this without public consent. But this risks public backlash without it. Public backlash could cost them their seat, so they have to be mindful of the public.
Because ultimately the law is written by politicians on behalf of the public with public approval. And the law is enforced by judges who have to interpret the principles behind the law and the purpose the law is intended for.
There is no dog whistle in this process. It is a purely functional one that needs clear definitions to create this equitable balance.
It's legitimate for interest groups who risk losing protections to ask for clarification of what their rights currently are and who they apply to (and who they don't). Saying 'what is a woman?' is about establishing who those protections within law extend to and where others might want to take the law in the future.
Clarification of the Equality Act which both the Conservatives and Labour seemingly both support is about this question of 'what is a woman?' So both are legitimising and effectively asking for discussion on the subject of 'what is a woman?'. Neither are saying it's a dog whistle because there is a recognition that the courts will end up with potential messy rulings on this which could lead to various institutions and organisations being left in a vulnerable position of the law being unfit for purposes and them being left high and dry and exposed to the risk of further legal actions needing to be taken to resolve conflicts. They are starting to realise that they can't continue to fudge this issue because it will and is coming to a head in our highest courts.
This is all about fairness and fairness in the eyes of the law. If the public don't feel a law is fair in sufficient numbers you start to see acts of civil disobedience and dissent. This manifests in conflict. Conflict which cant be ignored by politicians.
And round and round we go.
This is why the question is unavoidable no matter how much TRAs want to call it a dog whistle. It is completely central to the law.
And what REALLY pisses me off is the leader of the opposition was previously a human rights lawyer who fucking knows this and STILL is insisting on using emotional appeals to authority and refusing to come up with a workable legal definition.