The reason Dobson isn't on loan isn't because the Islanders need him to play every game, but I think it's more like the Islanders don't want to see Dobson get injured during the tournament. He represents "depth" for the Islanders. I think they fear that if one of their defenders gets injured and that in addition Dobson is not there (either because he participates in the tournament and/or in addition he gets injured during the tournament), that could put the Islanders a little bit in trouble. It must be believed that Lamoriello does not have much confidence in our defensemen in the AHL and that Hickey, at the latest news, was still injured.It's very dumb if he ends up sitting all of these games or even all but one or two over this span. The Islanders have six games remaining before the WJC ends.
In short, I think Lamoriello did the following calculation for the "worst possible scenario" and he thinks it's not worth it. Personally, I would have liked to see Dobson at this tournament. I am disappointed not to see him participate but I understand the reluctance of Lamoriello.