Overview of predictive modelling, machine learning, etc.

In these situations, it is not always necessary to think about samples and populations, or to think about a model that expresses a scientific idea. It doesn't make sense to me, because if I were to build a regression model I would still need to think about my samples and population. I don't understand why I should just plug my sample data into R and hope for the best without any idea my sample is about. The sentence doesn't add anything, it's confusing and technically incorrect. Instead the goal is to simply find an equation or algorithm that makes reasonably correct predictons sounds doggy to me.