CZ is true to his community he doesn't want people to expect a lot on crypto and maybe he warned them to be careful upon taking decision on which coin to buy. This is good gesture and hopefully many people didn't take it negatively since what he says is eye opener for newbie which think always good on crypto and they will not be rugged on it because someone telling them that its safe to invest together with they can get 100% sure profit on their investment.
It is better to say it as it is rather than giving false hope, some people want to hear you tell them they will become very rich in a few days when they invest in crypto which is not so.
it is good to be frank in matters like this, it can help a potential investor to make up their mind and be ready for the ups and downs of crypto.
CZ is a vivid example that if you are patient, dedicated and hardworking it will pay off someday, he didn't become this rich and popular overnight, he has work his butt to get this level and this can be same for all investors.