data science shouldn’t include any economics (except for maybe unsw because their data science is super weirdly structured)
That's probably a debatable topic, because Economics has a lot of similarities with data science. Some people think Economics is just applied Data Science on human's economic behaviours, and this is primarily because ds and econ uses EXACTLY the same method.
For example, in Economics, we use methods such as t-testing, linear algebra, regression analysis, ANOVA, and Machine Learning, etc.
These are all methods that comes from Data Science and Statistics.
But the main difference between Data Science and Economics is that most of the Data Science is about predicting outcomes, but most Economics is about explaining relationship between the dependent variable and the independent variable(s). So you could be arguing for both sides for this issue. The reason why UNSW's ds curriculum has Economics is probably because it's a very business focused uni.