That's unfortunately true.
I was thinking about it from the angle of the parser for the infobox parameter (Module:Pronouns's put()), which has no way about knowing about those pronouns not put into the infobox. The readers probably don't care about these or want to see them, but they do make the "exclusively referred to" phrasing incorrect.
There might be a way to get around this by just rephrasing the sentence preceding the "exclusively" list to instead communicate "this is the only pronoun set in their infobox"/"this is the only pronoun set used in notable instances", but I can't think of a concise, but correct wording that qualifies Noelle for this list but not Ralsei.
On the other hand, though, this page might be the best place to go into all the nitty-gritty details and codify exactly what makes pronouns notable for the wiki's purposes (as debated several times on the Ralsei thread).
I thought of suggesting persisting the parentheticals, but it would (besides adding complexity to the pronoun parser) only be useful for a few characters. Ralsei specifically has parentheticals to very precisely clarify the pronouns which have caused so much debate, but parentheticals wouldn't help with most other characters.
For example, Watercooler has no business appearing to be at the same "level" of she/her in the master list as, say, Queen or Orange — but adding a parenthetical to the main article would be redundant right next to Watercooler's other pronouns ("it/its,[1][2] they/them,[3][4] she/her[5][6]").