Okama as a fictional concept: sure, it reflects the writer, but it's also within a very specific context. Kiku is trans and nothing like them.
In any case, Oda is from a culture different from my own so the jokes he makes may not be the jokes I make and his original audience may also see them differently. And in the big picture it's not like he's got ill intentions with his depictions. So whatever.
but the comments I see online... yes we're talking about fiction but some of the views are still pretty awkward. "If ___ has ___ genitals they're ___." That sort of thing and some of the descriptive words used, it sounds like some of the posters don't get out much. Like they work in the part of the buildings where visitors don't go, lol.