To me, this would indeed be a misuse of noexit, but I still think that the roads should be merged.
I agree with how the wiki presents noexit=yes: as a supplementary tag that removes ambiguity from valid drawing. In other words, the data is still correct if you ignore the tag. Merging the node also seems incorrect for other reasons, e.g. mapping a wall between the two roads as you mentioned.
However, following mcliquid’s thoughtful suggestion that this might not be a noexit after all, I believe that the addition of noexit=yes in 2021 was incorrect, and there should actually be a single way with a barrier node.
@SupanchatMetta perhaps you didn’t notice (or didn’t understand) the noexit=yes tag when you connected the two roads?