This article isn't as informative or profound as you're making it out to be. They cite (literally) "TOP BITCOIN ANALYSTS" as one of their sources.

Here's the TL:DR for everyone else.

The decline prediction is based on basic technical price movement analysis. With the current decline we've dropped to the price point of the most second most recent peak. That peak is called the resistance point. Traders will pause when the price hits that level and then the price will bounce back up or it'll break through the resistance - technical analysis can't predict which way it'll go. If we break through this resistance level we could fall to the next resistance level at $6,400.

There's nothing unique about this prediction, every week we could make the same - going up 10-20% or going doing 10-20% claim. It speaks to the volatility of bitcoin, i.e., 20% swings are the norm, not the exception.

It is nice to see a negative price prediction post though!