It was an assumption and people say this because they are not trading but if they do this in real life, they will find out the truth about how hard is trading.
If I hear someone saying like this, I simply ignore it and never argue with him. I can't change one's mindset if it is already been closed to the reality. That is why I don't encourage people to trade unless they have positivity in mind and of course, they are willing to listen and open for some advice. Trading is not hard to understand but what it makes hard is that we can't make it perfect. No matter what we do, we still experience losses.