Because most people who trade by buying Bitcoin are still learning, and some of them still don't understand the difference between investing and trading, so they often think they're the same.
I don't see anything like learning, the truth is those people who trade by buying bitcoin feel that bitcoin is the best coin for trading majority of this people you feel that they don't understand the difference between bitcoin investment and trading bitcoin know the differences is just the fear of holding for Long term investment that led them into trading bitcoin, and sometimes this happens as a result of being curious to make profit from bitcoin, so they feel that trading bitcoin is the short cut to achieve thier target. So is assume that those who are trading bitcoin knows what they're doing.