I think you misunderstood the post...

because if the Saints win, they are situated as the #1 seed.

However, you're point is that they aren't guaranteed the #1 seed, which is true.

But the post refers to where the seedings are at the end of Thursday.

So, when the networks show the seedings and who is in and who is out, you'll see the Saints as #1 if they indeed do win Thursday night.