premise: How to smooth frizzy hair<br>Wash with a moisturizing shampoo. Frizz is often caused by dryness, so it's important to restore moisture to your hair in the shower. Always use a sulfate-free shampoo.
hypothesis: You can't smooth some frizzy hair.
reason: There are certainly some hair types that can not be smoothed. The article seems to be talking generally and doesn't include every type of hair texture.