Stearalkonium chloride is used in many conditioners, cheap or not, for it's anti-static, surfactant and antimicrobial properties.
Why would your hair go limp from protein? Protein sensitivities usually make your hair immediately straw-like, hard and brittle, not limp. If you think you have a coarse texture, there is usually no doubt when you react to proteins. Limp hair is a symptom of over conditioning and or lack of protein.