In general I don't disagree with this, but to be fair..something has come out, hasn't it?
First we had the Der Spiegel leaks, which of course the club says were misquoted and taken out of context (very possible, but I don't think we know the full picture) and then there's the very real possibility that the PL have had information from a whistleblower.
There's also the separate question of how widespread the conspiracy would actually need to be here. I'm not sure it's as wide as some are saying.
Of course this is going to be extremely difficult for the PL to prove, and the inherent implausibility will be a big part of City's defence. But we must admit the possibility that the PL do have some good evidence. I think that even if they were pressured into taking this action (and again that's very possible), it seems very unlikely they'd do so without a respectable basis. Personally, while I do think on balance City are more likely to be successful, I'd be surprised if the PL don't have a respectable case.
For what it's worth I say this as an experienced professional in an adjacent field who has investigated and litigated fraud and misrep cases of this magnitude.