I think you have a stricter definition of what an algorithm is than what is used in the context of this study. The general concept of the random forest algorith

I think you have a stricter definition of what an algorithm is than what is used in the context of this study. The general concept of the random forest algorithm (for example) is the same in each implementation but the exact details of how that general algorithm is implemented (the exact algorithm) is most likely not the same. Therefor, you shouldn't expect to get completely identical results regardless of how much data you train them with. They should all be in the same neighborhood though, which they are, for the most part, in the results from the study.