No, it has nothing to do with accent (phonetic). It's entirely language. They have a long history of "forbidding" words that are "real or not real spanish".
And by the way, counterintuitively, languages have NOT evolved to be better understood, but on the contrary, to "separate" or create cohesion in smaller groups.
"Spain" is not forbidding anything, the RAE [1] and the ASALE [2] are working together in keeping a common tongue. Don't allow some chauvinistic view to cloud your judgement.
And by the way, counterintuitively, languages have NOT evolved to be better understood, but on the contrary, to "separate" or create cohesion in smaller groups.