Machine learning has the problem that it can appear to be a bit of a 'black box' when processing information. You put in your question and you get out an answer. The answer isn't necessarily correct and if you ask a stupid question (like "what handwritten digit is this dog?") you will still get an answer.
Machine learning techniques are becoming more of a part of our daily lives, used by companies to make decisions but with no human in the loop, it can be hard to challenge. Google have a set of AI principles they work towards which I recommend reading but boil down to: