The downside in this argument is that forex robot systems do not claim to be perfect money making systems! They are systems which implement certain strategies (technical market analysis techniques) which real traders have developed and used, and they make those strategies available to anyone with a PC and an internet connection.
Those forex traders believed that expert analysts could analyze the past performance of the market, and thereby predict the future. They particularly used information such as price movements, and volumes of trades, and they developed techniques such as charting (candlestick charting), Dow theory and Elliot wave theory. No one claims or expects that those techniques will always get it right. They just need to get it right more often than they get it wrong so that traders make an overall profit on their trades.