Some people refer to latticino as only the white. Other people include the colored type as well. This makes sense, really, because the colored variety is often made by using colored lattimo. The color is either on the surface or in the filaments themselves. Lattimo in the US is called milk glass. Colored milk glass is called things like black milk glass, pink milk glass, etc. The same can, in my mind, be said for latticino. Insisting the lattimo only be the white variety may be being a bit too picky.
I don't think either school of thought is wrong. One can get around the words by calling the twists zanfirico. The only problem here is when it comes to selling. People usually use the keyword "latticino," and not "zanfirico." So merchants use latticino for the sake of the people looking for this type glass.