I would sort of agree but would rather say on the subjects most likely to be an issue to the players; since the average game has the PCs all being rokugani-born samurai.*
So the fact that a player would be told a character they can self-identify with wouldn't "fit the setting"** when it's a completely artificial setting (let's be fair, it isn't and has never been an especially accurate portrayal of feudal Japan, has it?).
By comparison, the whole hiemin thing is less of an issue; just by existing and expecting the standard of life the rules tell them they should be accustomed to the PCs are consuming a huge amount of the economic activity of a vast number of heimin families somewhere and in practice they're not giving anything back***. Westerners are quite good at not thinking about where the labour that makes their cool T-shirts and electronics comes from, and as long as they're not playing said characters and hence stuck at the wrong end of the 'violence inherent in the system' themselves, I don't see
* though watch this space for the Path of the Waves supplement and/or the PDF release of the Highwayman adventure.
** as a complete aside, if someone does want to try an 'accurate' historical/mythological setting but has an issue with gender/sexuality impact on their player base, look at Mythos/Heroic age Greece. Seriously, that lot (divine as well as human) would go for anyone and anything if it was gorgeous enough.
*** okay, 'protection'. But since the main thing they're protecting against is other samurai, lost or otherwise, that's not really offering anything that couldn't be achieved by the entire samurai caste buggering off. Which observation is basically how some branches of the Kolat got started, thinking about it.