I'm going to assume, against reason, thwt this comment is not made in bad faith.
The racism is in the action and the intention. You can jork to whoever you like but going out of your way to replace depictions you don't like is weird. This isn't a case of some guy making a pin-up of a woman he finds attractive. It isn't a remix: the edit has the same clothes (what little there are) and the same tattoos. So the statement is "I want this same person but I want them white."
Even replacing the ethnicity with an entirely new character would be weird, but the direct ethnicity edit cannot be anything but offensive in intention.
The world of (Western) representation has been overwhelming White. Racism isn't just prejudice: it is prejudice that is empowered and entrenched by systems, both legal and cultural. The removal of a non-white character to instead endorse yet another white model (whose features are inline with the archetypal Aryan of White supremacist fascination, e.g., blonde, straight-haired and blue-eyed) is a minor salve to a system that is being stressed by a slow cultural push towards equal representation. And, yes, a sexy lady with dark skin for a video game can be representation but I don't have the will now to get into the "why."