I wonder why the supporters of the multi-hub strategy really only hate SK for that, and have nothing against KL or BA or LH for not opening a hub in ARN and OSL (or CPH for that matter). Is SK the only airline they want to kill? If its about convenient and profitable connections, this should be as convenient for you and as profitable for the ariline if we talked other operators than SK.

PS. There is some difference between starting a completely new destination from ARN (like HKG) and opening a duplicate (like EWR). In the latter case, I believe, SK does this because there is traffic out of ARN to EWR that is sufficiently good for business, and it does not really hurt the passangers connecting in CPH to EWR, as this traffic can still be captured by CPH-EWR connection. Opening a non-duplicate route from an alternate hub is quite a bit worse. Because SK does not offer a good network of feeding flights to ARN. So the connection becomes essentially unavailable for PAX from German, Eastern Europe and alike. Given the language distribution in TATL cabins, I do not think that this is an ignorable part of the market (it is worth remembering that PAX connecting in CPH are not only coming from OSL and ARN).