These guys involved in the manhunt this summer in Northern Manitoba were showing off their largely non-black rifles. And at least one suppressor, which is decidedly black. Not sure why they'd need to shoot suppressed, unless perhaps to protect their hearing... anyway, yeah, for brush/grasses it kind of makes sense to avoid a black rifle I guess, but I'd avoid black sunglasses and magazines and whatever other stark black accessories if involved in a search for someone who might shoot back first.
For critter hunting, maybe not so much. In my experience with painting airguns, the result usually looks kind of grubby after less than a year of use. It's not always practical to thoroughly scrub one's hands before picking up an airgun to avoid getting the light coloured paint grimy.