Yes, -cones are prevalent in hair care products. And yes, many long haired people refuse to use products with -cones. HOWEVER, I do believe that -cones are not necessarily all bad. If you regularly moisturize and clarify, there will not be any buildup of the -cones. It is the build up that causes the damage, not the -cones themselves. When -cones build up on the hair, they prevent any moisture from getting to the hair. This effectively suffocates the hair which then causes it to become dry and brittle, causing breakage.
Using a clarifying shampoo and/or using a vinegar/water rinse after shampooing, will allow the hair to absorb the necessary oils and water during the conditioning. This allows the hair to be re-vitalized.
Some hair types cannot tolerate the -cones at all. If you find your hair "sticky", crunchy or very dry on the ends, I'd recommend clarifying and oiling the ends before using the -cone products again. Taking a vacation from the -cones for a few weeks will usually tell you whether or not you hair likes or dislikes the -cones.
The advantages of the -cones: reduces frizzies, improves shine, covers/repairs minor split ends, makes for easier detangling.
There are products out there without -cones. Products that have more natural ingredients typically do not have the -cones.
I've said it before - everyone's hair is different. What works for one person may not work for another. If you find something that works for you for more than 2 weeks - it is probably something worth sticking with the routine.
Hope this helps a bit.