Even if you were to completely deny any scientific nature of economics, it would not be reason to lessen the "memorial price", as there is no implication that "Nobel price" means science. 40% of the original five have nothing at all to do with science and even if you dismissed the peace price for being the odd one with all the norwegianness and questionable recipients, there would still be literature . Just think of the memorial price as "the Nobel for economic literature", you won't find a hair in that.

(Also I suspect that there might be some linguistic misunderstanding here, maybe some participants are used to think in a language where the most common translation of "science" does not include the subset of social sciences?),