Quote from riskfreetrading:
Why are there people who buy after a market move up, and then starts coming down, and they continue to buy. For instance, I cannot explain why anyone would buy the QQQQs and the Dow after 1:45PM today. The market is coming down. So what is in their mind to tell them to buy a thing that is coming donw?
simple - momentum traders who buy strength on pullback on larger time frames than what you are trading. Maybe they know something.