"Sexist" is a very inappropriate word in this context IMO. I know that many people don't read the descriptions, possibly they don't know it's there, or don't know how to easily access it.
However, I don't mind. If someone asks, I'll clarify, if not, then I'll simply ignore it unless it gets picked up and brought as topic into the conversation by others.
IMO, it is the same as with persisting typos: you either ignore them, or you send a simple /tell to give the other the chance to know. In no case do I make it significant for my RP. Occasionally I use "/me is female".
Regarding the question of nipples: I've pondered this myself, and my conclusion was that the settings gives the answer: basically, it states that the races interbreed heavily, and that whatever parents there are, the child is one race or another, with the only exception of the Ynnwns. Therefore, Klyros must be genetically compatible with the other races, and if this is the case, then the reproductive system necessarily is compatible as well, including secondary reproductive organs. Therefore, I've come to regard all except the Kran as "races", with Kran being "species".
The necessity of mammalian secondary reproductive organs like breasts then mandates that females have at least a slightly different form than males. However, given that even in RL humans these features can be blurred or completely hidden by other features like muscle, it is not necessary that the female Klyros be obvious to everyone.
Given their otherwise reptilian / fishy / batty / whatever properties, the likelyhood of such a comparatively minor visual difference is comparatively high, especially since their other environments may dictate more similar forms, anyway (for streamlining, for example).
So I think they're less obvious, but still distinguishable upon closer visual inspection.