I suspect that the author of this is not, in fact, particularly perplexed by what the EU is doing in these negotiations: they clearly see the UK as part of their sphere of influence and want to make an example of us to discourage the others. However, their public position is that they're absolutely not doing that and that this is a perfectly normal trade negotiation with perfectly normal terms that, in any case, the UK has already agreed to. This document is basically taking that public position and pointing out that it bears absolutely no resemblance to reality.