The quoted article is first and foremost a deck tech rather than a serious rules primer, so it shouldn't come as a surprise that it's going for humor rather than in-depth rules analysis. To explain the interaction it mentioned: If
The Scarab God's ability is used on
Vizier of Many Faces and that token copies,
The Scarab God, the token is a 5/5 blue-and-black non-Zombie. This is for the same reason that a
Vizier of Many Faces that you cast from your hand (and copied the God) would be a 5/5 blue-and-black non-Zombie: Vizier's copy effect overwrites its “normal” characteristics.
To go a bit more in depth, as the Scarab God's ability resolves, it wants to create a token-Vizier that looks like this:
Vizier of Many Faces - {2}{U}{U}
(Black) Creature - Zombie
You may have Vizier of Many Faces enter the battlefield as a copy of any creature on the battlefield, except if Vizier of Many Faces was embalmed, the token has no mana cost, it's white, and it's a Zombie in addition to its other types.
Embalm {3}{U}{U}
4/4
However, before you can put that creature onto the battlefield, there's a relevant ability to apply: its copy effect. You choose to copy The Scarab God, and that overwrites the above-described characteristics with the ones it's copying from The Scarab God, so it now looks like this:
The Scarab God - {3}{U}{B}
Legendary Creature - God
At the beginning of your upkeep, each opponent loses X life and you scry X, where X is the number of Zombies you control.
{2}{U}{B}: Exile target creature card from a graveyard. Create a token that's a copy of it, except it's a 4/4 black Zombie.
When The Scarab God dies, return it to its owner's hand at the beginning of the next end step.
5/5
As you can see, the token is not a Zombie and is a 5/5 because that's the characteristics it copied from the Scarab God–the “normal” characteristics were overwritten when you applied the copy effect.