FUD is at play
The HMRC IR35 CEST tool is well known to give bad answers. I think that this is deliberate as the result is that companies will not use it for fear of being bitten by a court case some time down the line.
The result is that companies will play exceedingly safe - thus the blanket 'no contractors' positions that many are adopting.
I am upset that my government is playing silly buggers and trying to pull a fast one - but looking at what their political masters have been up to for the last 3 years I do understand where they get it from.