I didn’t see it as any more difficult. Instead of saying ‘I want to remove orange cast’ and thus reducing predominantly red and secondarily green, you can say ‘I want to add teal cast (opposite of orange)’ and thus increase predominantly blue and secondarily green. @afre’s post giving the greyscale of each channel gives us the clue why. You could achieve r=g=b either way, but the former would be dark, while the latter would be bright. That’s why I started by determining which channel I wanted the brightness of - R - and matched the others - B and G - to it.
Yes in most cases G will have the best information, but not so in this example, under very orange light.
There are many ways to (colour the) skin (of) a cat.