Humans are humans, and to that extent, one can use prior event correlations to predict possible future scenarios or draw comparisons between past events. If history was entirely irregular and people, unpredictable, then whole fields of social science would seem futile (economics, poli sci). But actually "repeating" history is a huge leap from there. There are so many variables affecting each historical event, and scenarios with superficially similar details can turn out completely differently. It's not an equation of x + y = z, it's one that uses every letter from any language as a variable, half of which might decide to do different things at different times depending on if they felt sick that morning, couldn't come into work that day, or had a little too much to drink. One can only say anything has been repeated when speaking in terms so broad that they start to lose significance, or ones too contrived to mean anything.

More than anyhting, the phrase is a cliche warning people to consider the results of past actions before taking that same action. So in that, it's at least well meaning. But if an action has resulted in something in the past, the only thing proven is that it's possible it could happen again. By no means does it suggest it will, should, or even is at all probable.