I don't know whether MAG has made any press release about a slowdown in growth but his comment about the second runway and lack of demand is just typical of some of the poor journalism we've come to expect these days.
Perhaps someone should send him a copy of the official opening hours of R2 and ask him if he still believes his inflammatory use of "scarcely" is justified. If he looks at FR24 between 07.00 and 08.00 in a morning for example when both runways are in operation, he might just notice there can be a fair bit of holding for inbounds, sometimes more than LHR. Yes, there are quieter periods during the day even in summer but that doesn't mean his comment is justified.