A great touring bike can be built out of any material: steel, aluminum, titanium, and yes, carbon. There is nothing inherent in carbon that prevents it from being used for touring, it simply has to be designed for the purpose and very few carbon bikes are. Unlike the metals, carbon is not isotropic (equally strong in any direction) and every expected load must be considered and designed for. It is possible (but very unlikely) to design a carbon bike that only fails while towing a trailer.
I think there is no reason not to consider using a carbon bike with a trailer, but just like other materials, stay with the stronger, stouter models. A super-light carbon wunderbike is just as poor a choice as a similar steel bike. It's not the material, it's the design.