A profit warning is to let the market know, as soon as is reasonable, that the company will not make as big a return as it was expecting when it made its forecasts. In the case of Apple, it does not mean that they are losing money. It does not necessarily mean that growth figures are not in the double digit percentages. It means that however good the growth was, it was not as good as they expected.
In the meantime, as you would be aware from the press, initially Apple were being assured by the authorities that their products would not be part of the trade war activity. But then they were. If you want to blame someone, blame China for manipulative trade practices. And then, it you are really unreasonable, blame the USA for taking China to task over China's unfair and manipulative trade behaviour.
Or, of course, if you are an "entitled" investor, who wants big returns but doesn't understand risk/reward, and thinks they can get away without losses, obviously everyone but you is at fault, and they all need to be sued.
