Yes, blame the tool
When it first was released (I haven't checked it since, but I doubt it has changed), the only question that was of significance was 'Are you allowed to substitute', it didn't matter what you answered to the rest.
If you answered 'Yes, I am', then you were outside IR35, if you answered 'No, I'm not' then you were inside IR35.
From what I can see, this is the usual heavy handed approach from HMRC, relying on the agencies, and some public organisations allowing themselves to be bullied, instead employing some capable lawyers, and forcing the issue, relying on the evidence, & results from the last time HMRC tried it on.
There are public organisations who have stuck two fingers up to HMRC, and told them quite plainly 'NONE of our contractors fall within IR35'.
I would like for someone who is close to Jeremy Corbyn, to ask him to publicly promise to repeal IR35 as soon as he takes office (Hey I can hope, can't I).