Why does the media say eating "gluten free" can reduce glycemic spikes as gf still allows rice and buckwheat which is high carb?

The Media is Wrong: Good observation. "glycemic spikes" are due to carbohydrates not gluten. Gluten is found in wheat and many people who go "gluten-free" subsequently reduce their carb intake. Changes in glucose control attributed to lack of gluten are actually due to carb reduction. For people who have celiac disease, going gluten free is important. There is little evidence that it helps others.