The new signs are in just as much violation of the Manual of Uniform Traffic Control Devices (MUTCD), which is the standard for roadway signage in the US. However, the state of Florida has no control over the signage. Generally, the MUTCD is enforced by the federal government through the allocation of highway trust fund revenue (federal gas tax plus general fund dollars that are given to states to build the national system of highways). Since Disney doesn't get any money for this (and I don't think RCID does, usually either), they can do whatever they like.
Personally, I prefer the blue over purple, but would like MUTCD standard coloring better than both. But I think color is far less important than symbology, and I am disappointed to see the old style lane assignment arrows (the downward pointing squat arrows which have been phased out over the last ~20 years) are still in use on the new signs. The new arrow design is the narrower upward pointing arrows that includes turns and divergences in a more intuitive fashion.