I love how he’s so bad at explaining his own stupid arguments that people who actively dislike and disagree with him have to do it for him.
He does sort of explain it, he just doesn't want it spelled out this much (and admittedly I've engaged in reductio ad absurdum). If I wanted to be pretentious I'd say I was doing a Straussian exegesis. He has an exoteric message designed for the hoi polloi, and an esoteric message for the hoi olligoi, his in-group, that is deliberately obscured. Kind of like a Motte and Bailey argument.
If you drink the kool-aid and are well meaning and do what you think is the "kind" thing, like I used to be like and still pretend to be outwardly, he's presenting one form of argument. He's a man who wants to be a woman, but that's not a nice way of saying it, so we say he's a woman trapped in the wrong body. But that's an unkind way of saying it, so we say he's a woman in a woman's body (because the body belongs to a woman), it's just that body has the wrong chromosomes so she just needs medical help to make her body match what it's supposed to be. But he's biologically male, except talking about biological sexual categories isn't nice to intersex people (it's not nice to call as CAIS woman a male because she's XY but immune to testosterone) and also you don't always know someone's intersex status.
So the nice and kind thing to do is say that Abigail is a woman who had a hormone imbalance that needed treatment, and also because that hormone imbalance wasn't caught earlier, she might need some additional surgeries to help her recover from this endocrine disruption and make her body match what she feels it's supposed to be. Trying to say her feelings around this are pathological (gender dysphoria) and she needs to be diagnosed with it before she can get that treatment (specifically in a separate system with long waiting times) is treating her differently purely for being trans.
You then get into the argument around consent. Imagine a 22 year old goes to the doctor and says she definitely never wants kids and wants a hysterectomy because she has very bad endometriosis that has not responded to treatment. And the doctor says: I knew a woman who did that at your age, and when she met a man a few years later, she fell in love with him and wanted to have his babies. But she couldn't have them, and he wouldn't consider marrying anyone who couldn't give him biological children, so she killed herself. So I'm not going to let you get sterilised, in case you one day meet a man and you kill yourself because you can't bear his children. Well that's terrible! He's denying her bodily autonomy based on a hypothetical. And in British medicine we have the concept of Gillick Competence and how a child can decide if they're sufficiently mature that they want or don't want certain treatments (which is why teenage girls can get the pill without their parents knowing, or get a covid vaccine if their parents were anti-vax).
Therefore, if a child decides they want to go on puberty blockers and they're judged to be Gillick competent, their parents or the state should not intervene to stop them, because it's forcing them to go through hormonal changes they don't want. And it's victimising them just for being transgender, when a cisgender child who was experiencing a similar endocrine disruption would be helped. The distress they feel at this can lead to them killing themselves - this isn't gender dysphoria, it's just like a child getting some freakish pituary tumour causing endocrine disruption getting told they can't have it treated till they're 18 and to "just live with it". Evil doctors who hate trans people use the concept of "gender dysphoria" to pathologise the distress transgender children feel about their endocrine imbalance in a way that they wouldn't do to those cisgender children with pituitary tumours.
The exoteric message is "trans kids need help and you're saying no! To object to this is transphobic and means you want trans kids to die!". The esoteric message is what I've just laid out. Ollie doesn't want normal people to understand his argument properly, he wants them to trust him as an expert and deliberately muddies what he's saying to prevent you thinking it through.
Because if you think through what he's saying, there will come a point where you say "wait, hold on, that's not the same thing". But you can't say that to any of his arguments without being unkind, and so therefore he'll shut you down as a transphobe, and people won't hear what ludicrous logical jump you're criticising and just hear you want to hurt trans kids, and his line of argument is too muddied for them to realise for themselves because again, it's the esoteric hidden argument that's deliberately obscured from them.