Paragraph 24, referring to the EU regulation that I’m too lazy to unearth right now the ECJ has to suffice:

Furthermore, it is clear from that wording that clarifying or descriptive terms indicating the plant-based origin of the product concerned, such as soya or tofu, at issue in the main proceedings, do not fall within the terms which may be used with the designation ‘milk,’ in accordance with point 1, second subparagraph (b), since the alterations to the composition of milk that the additional words may designate under that provision are those which are limited to the addition and/or subtraction of its natural constituents, which does not include a total replacement of milk by a purely plant-based product.

I would expect the same reasoning to apply to “I can’t believe it’s not” type of deals but I’ve never seen that kind of stuff anywhere in the EU anyway, also before that judgement, someone else would’ve tried it if it was legal. Probably just general misleading marketing kind of deal, the same kind of strictness that gave us “serving suggestion” in fine print on a pack of trail mix with a couple of raisins and nuts in a bowl. The package doesn’t include a bowl? Who would’ve thought?