Bruce Banner is white, but he is not Hulk. Hulk is an independent entity from the other side of The Green Door that leads to the gamma reality and Bruce Banner became his conduit when blasted with grammar radiation. Hulk existed long before Banner. Hulk is green.

Source: Am nerd, and also a huge Donny Cates fan. His Venom run is top drawer, I tell you. TOP. DRAWER. Seriously, though, it’s so good and did the characters of both Eddie and Venom so much so long overdue justice.

Edit: There are also multiple different Hulks (technically the same psyche, but different manifestations) that can manifest through Bruce, so while Savage (classic/true) Hulk is green, Hulk, as an entity, can also be Grey, or a slightly different green with better hair and verbal skills, or a fuck-you-scary-demon-dad-thing, among others.