It is and will be in large part their market, so it does matter.
It didn’t “NEED” to be, but the nature of the medium/media they employ allows that it can accommodate with very little additional effort. Whether it is choosing an avatar with a different skin tone or other characteristic, or options for NPC appearance, that it doesn’t need/want to be any different than it is for a select segment of the market is a viewpoint of exclusion whereas the small additional options that provide a wide spectrum of balance allows for a viewpoint of inclusion that also includes the current rendition of the game.
Basically developers have the option and large swaths of their audiences want them to exercise that option to inclusion, not exclusion. Yes, there are a few GG fools arguing for exclusion, but who the hell cares?
And really, these developers claim that RPG is their lives & livelihood… Since when is restricting skin tone something anyone with a grain of sense thought a good idea in RPG. It ought to be the players choice, so when it is so easy to do, why not, especially when not doing so hurts the dev in the end?
