Because tutorials often aren't featured here. Especially not video tutorials. If it introduced a concept or something it would be more in line what's normal on here. As a Javadeveloper for many years for which this could be relevant, I'm not too interested because it's not selling why it's useful, just diving into lots of code. So to be a bit blunt, but I don't think the quality warrants being on top.
And I know one's not supposed to speculate, but multiple upvotes in short time without any discussion for something of this caliber is a bit off.