You probably do feel withdrawel symptons when you stop smoking Cannabis, but I imagine you only get withdrawal symptons if you go from smoking frequently to not smoking at all or nearly not at all.

Again, i'll refer back to fruit (lol). If you were to eat fruit every single day, like clockwork, and then suddenly you stopped eating fruit, you would experience withdrawal symptons.. This doesn't mean that fruit is addictive, it just means that you had grown accustomed to eating certain amounts of it or at certain times.

Same for weed.