I do not think that coconut oil treatments should be treated the same as protein treatments because they have different qualities.
Although coconut oil penetrates into the hair shaft and helps to prevent protein loss within the hair strand it is not a protein so it cannot replace the protein that has been lost if the hair has been damaged.
Coconut oil has many properties, it is an emollient (softens and smooths), a hair conditioner and a skin conditioner. However, I find that coconut oil works best when it is emulsified, this stops it from getting too hard when the temperature drops.
I agree it's strange that protein treatments can cause breakage when they are meant to help the hair, but it's all about balance because too much of a good thing can be bad.....