Excellent point. Many more could be made, but having had many discussions with die hard modalists like the author and poster of this article, it's not worth the effort right now. They always fall back on such nonsense as when the Three Persons of the Godhead are talking among themselves, and having a subject-object relationship, that it's Jesus talking to Himself and having a relationship with Himself.
That kind of illogic is hard to have a rational discussion with.
Reminds me of a oneness pentacostal I know. He started trying to explain his position by saying that the Trinity represents an ancient sun god that was worshipped prior to christianity. I'll stick with 1500 years of orthodox teachings instead joining the cults,muslims etc on this issue.