I think you misunderstand.
Like most people, i am aware of how well Finland has done in Worlds over the years and you're right that, as a country, it has a good history at worlds.
However, Esa has won Finnish Nats 6 times. In fact he has only not won it once! Therefore i think it's completely fair to assume that Esa is, far and away, in terms of Nats, the most consistent player in Finland and the most likely to win.
What he's saying is that just because Esa won with a deck is not necessarily indicative of a "best deck in format" because, as history has proven over the last 7 years, Esa tends to win, regardless of the deck he plays.
No disrespect to Finland whatsoever, but you can't deny that Esa almost invariably wins Finnish Nats. Therefore, saying a deck might not be AMAZING because he won Finnish Nats with it is a fair comment. I'm willing to bet he'll win next year, regardless of what he plays.
P.s. Congrats Esa!