It is not that the trade is bad when purchasing at a lower price than your first trade. However, the terms "buy the dip" or "average down" when read by sheople will typically create bad trades.
Experienced traders "buying the f'in dip" or "averaging down" will have good returns as they know and understand the action.
IMO the terms should be tossed out the window, and every trade should be treated as its own entitity with zero emotion and 100% objectivity.