More troubling in hair care products than silicones are Cationic Polymers. These ingredients like Guar Hydroxypropyl Trimonium Chloride or Polyquaternium-10 have been demonstrated to build up on hair. They ionically bond to hair and you do need to shampoo more to get them off. Silicones don't stick nearly as well as those ingredients.
I wonder why there is no controversy about Cationic Polymers?
I am very interested in following up on this, mostly because I believe cationic polymers are indeed far worse than anybody cares to talk about. My objection to them is based on pure experience -- nothing scientific. Since going CG, I have definitely noticed that stylers with polyquaternium-10 and -11 leave residue on my hair that requires more than a conditioner-wash.
I'm going to be doing some research on this in the next few days and will keep you posted.