The choir leadership should be able to take corrective measures. For all the talk of acceptance, tolerance and Christian charity within the church, the choir is still a collective and co-operative group within which all participants need to understand their roles and the context of their tradition or mandate.
My parish choir has a woman who graciously accepts the (only occassional) solo as a matter of her commitment to the church, and I think she does so without an ego related agenda. Her phrasing and breathing and timbre can be quite different for a solo than when choral singing, and frankly it works.
We're pretty old fashioned, so we tend to sing without modern contrived "cute" articulations. Typical I guess where our combined experience would number several centuries, but there seems to be a growing respect for our older, rather English in our case, style of choral singing. After all, the idea is to lead an engaged congregation and that would be pretty hard if we all sang in personal, contrived, artificial and conflicting styles.
Oh, we have our troubles, like regular attendance, money, and overly commited members, but we struggle on, even when the director rides us about "words, words, words!".
My Dad (who composed some church music) used to joke that "The church's one frustration is in the chancel choir" to the tune of Aurelia. He knew wherof he spoke.