It's a humane message of open-mindedness, emphasizing acquiring knowledge and bucking the crowd.
It's unclear why the filmmakers chose to give the Vikings Scottish accents, fusing Norse and Celtic mythology. But why quibble with funny and likable characters voiced by Craig Ferguson and Butler? Their Scottish burrs make the banter all the more amusing.
But in the end, it's the bond that develops between Hiccup and Toothless that leaves the most powerful impression.