That summary makes no sense. The EEA Regulations 2006 Regulation 21B(2), which 19(3)(c) depends on, says,
The Secretary of State may take an EEA decision on the grounds of abuse of rights where there are reasonable grounds to suspect the abuse of a right to reside and it is proportionate to do so.
(This text is now Regulation 26(3) of the EEA Regulations 2016.)
If the clause be valid law, then abuse does not even have to established on the balance of probabilities, let alone there being an obligation of proof on the SS. Perhaps the judgement will say that the clause is contrary to law, in that there is an obligation on the SS to demonstrate that abuse has occurred or was planned. Otherwise, where there is a reasonable suspicion, but no more, of a marriage of convenience, the non-EEA partner cannot be immediately excluded, but instead, the EEA partner may first be expelled, and then naturally the non-EEA partner remains excluded.
ECOs are already refusing spouses family permits on the basis of insufficient evidence of a relationship, but that might be from confusion with the rules on settlement visas, and it might not be systematic.