Two factor auth is defined as something you know plus something you have.
Two-step verification (also known as two-factor authentication) is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network. This is a special case of a multi-factor authentication which involves the presentation of two or more of the three authentication factors: a knowledge factor, a possession factor, and an inherence factor.
Their point was, there's only one factor here: something you have. There's no password you give the site. So it's one factor. It is probably significantly safer than just a password, since nigerian hackers can't steal your phone from a huge poorly secured database.... but it's still just one factor.
Two-step verification (also known as two-factor authentication) is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network. This is a special case of a multi-factor authentication which involves the presentation of two or more of the three authentication factors: a knowledge factor, a possession factor, and an inherence factor.