I feel like there would be a case to answer if it went to court in the UK, Scrabble words are not an entirely arbitrary selection, nor are they all words in [most] regular dictionaries AFAICT. The list has been curated in order to provide a specific set of rules for a game: there seems to be a creative act of compilation. To say it another way; it's a factual presentation - but the fact (of which words are in the list) was created for the game.

This makes it unlike an almanac, say, where the list is dictated by past events.

It's perhaps similar to the Guinness Book of Records, where the choice of records to present is creative (along with the usual creative aspects of a book, composition of pages, choice of accompanying images, etc.).

One consideration a court might take is that the list cannot be generated without copying from the established Scrabble Dictionary because one otherwise would not know whether to include or exclude any particular word. A list of 'all existing English words of 1-3 letters', say, would be fine though.

That may have been true in the past, but the game is now over 75 years old. There is just absolutely zero chance that the inventors of the game would have been more motivated to invent if they were given a longer exclusive term. Since the stated goal of copyright is to advance the progress of the arts, there is no justifiable reason the public should continue granting exclusivity to the game at this point in time.