The situation doesn't really change though, other public transportation doesn't have bathrooms either.
Other public transportation, like The Bus (is there another?), have stops directly in front of or next to businesses, malls and public areas that do have restrooms. The Rail, however, has stations that require you to walk -- in some places quite a ways -- to find a restroom for public use.
I invite you to research the stations here:
https://honolulutransit.org/about/route-map/Click a station, then click the View Station button for photos. The majority of the surrounding area at every terminal is for parking, bus pickup and drop off, Handi-vans, etc. Any businesses are several levels down to street level and another block or more past the stations. The Bus isn't that way. if you're in the same areas The Rail runs, The Bus can drop you near a restroom.
Besides, are you really arguing for lack of facilities because other city/state services are just as poorly designed? is that the standard now? "The Rail only has to be as good as other public trans systems, so let's save some money."