"Business logic" seems to mostly be code for just that - really basic math (and often convoluted conditionals) that can be implemented (badly) in a spreadsheet (augmented by basic scripting), by people who aren't competent programmers, aren't interested in becoming so, and aren't interested in paying for someone who is to do the work for them.
And lets be honest, that last one is actually a pretty reasonable position considering the difficulty in evaluating the competence and integrity of anyone claiming to be a competent programmer for short-duration contract work.
And frankly the first two are as well - these are people hired as office workers - if they had the skill and desire to become programmers, they mostly wouldn't be there in the first place.
Scripting and "business logic" is basically the badly programmed glue that holds together projects not worth hiring a dedicated programmer for. Or at least that's where it starts, though like any program feature creep feeds its cancer-like growth, potentially fueled by business growth until you've got something so large that it really should be done right, but now it will take years of expensive programmer time to re-implement properly without breaking anything.