Not sure what was up with their menu, but the one listed for 2/17 has the following in entrees:
Day 1 - whitefish
Day 2 - Salmon AND a seafood linguine
Day 3 - Sole
Day 4 - Salmon
Day 5 - Fish & Chips
Day 6 - Tiger shrimp
Day 7 - Salmon teryaki
So yes, a bit of salmon, but that is not the "only" seafood on the menu. Unless they only did main dining on the nights where the seafood was salmon, but then that's inaccurate info to say "they only had salmon in the main dining room" as a blanket statement.
(No, not an apologist - my upcoming could be my last Royal as I think Celebrity fits me better with occasional Disney thrown in. And I despise seafood. I was just looking to see if that were really the case.)