A lot of curlies have no problems with silicones, but it's when you remove them from your hair you may see that it has totally dried out your hair and it's hard to grow your hair if your hair is dry and brittle and keeps snapping off.
Water soluble silicones aren't bad, they wash out. I'm a fan of Biolage, but I've been using it for years and with the use of everyday shampoo and high heat, I lost my curl.
Though specific cuts "enhance" your curl, make sure that whatever you're using doesn't damage your hair, dry it out, and/or give you split ends. Also, the other reason people in these threads were trying to avoid conventional/commercial shampoo was for irritation, allergies, and chemical exposure purposes.
Do what works best for you and what you're okay with in terms of chermicals. There's a range in what people accept in their homes and on their bodies. Some people use every chemical combo known to man on themselves, others don't use a speck. I personally find a happy medium to suit my lifestyle, but again, do what works for you.