People will say this when it falls from 1,002,000 to 990,000.

I think the reason is that most people want to have their current thinking validated, even when there's a long track record suggesting they're wrong and always have been. It's almost like tunnel vision and cognitive dissonance.

They could just as easily say that it's up, but they choose an arbitrary point in time that allows them to forget that they were wrong so they can keep making the same mistake. It's a vicious cycle.