Because nothing really ever happens because of random chance. Everything has a reason, and to pretend it happened because of random chance is to say you don't care enough what the reason was to try to figure it out.
But beyond that I think your comment misses the larger point: it's exceedingly rare for something to happen for "a reason", most things, even in a deterministic universe, happen due to the combination of multiple factors. Sometimes we can model the cause and effect in simple terms with some success, but in other situations (e.g. wheather forecasts) we deal with nonlinear and chaotic systems that we can't really predict very well.
Not the “since everything happens for a reason, let me inquire and dig deeper to figure out what was the cause” person. And my point was I’m surprised more people don’t attribute things to random chance cuz it’s an easy out. Again, not the people that actually care about finding things out, Im talking about the astrology type