Who's to say it was A.R.M's idea for the Rainbow knock off. Ride owner's when buying a ride new from the factory pretty much have the option to have whatever artwork/colour scheme they want. Also there is the possibility that the ride has been re-themed in its lifetime out of the factory.
I don't think it looks that bad, although its no Huss

I have seen some very average looking Ali's in the flying carpet theme.