Edit: because some people are confused about this: nobody died. The cancer thing is just an example. We can substitute in a car accident and it would be effectively the same thing, the person is saying that X happened and there was a reason that X happened (not to be confused with cause). People also like to say things like "well the universe is trying to tell you something".
I don't understand how people can think that. You want to tell me there's a reason that a 4-year-old kid died from cancer? Nah, there's no "reason" for that.
You tell me that you can take a lesson from everything that happens to you? Sure that makes sense. But sometimes the lesson is that life is fucking random and bad things happen to good people. And that 4 year old isn't going to learn a lesson except that life is random.
I feel like the people who say that everything happens for a reason are trying to deal with the randomness of life. Which is understandable but I don't think it's helpful. I don't think it helps you deal with the world as it is.
I'm talking about people over 40, if you are wondering. Seems to me they should know better.