That's fair. It sounds like they wanted to iterate on something that's been established on a preliminary basis, which makes the choice to stay within the parameters of of the original study likely the correct one. We have to be choosy about which variables we tweak when building upon previous works, otherwise people will correctly point out ambiguities if not outright flaws in reasoning when the authors analyze current results in the context of the previous study (the whole point of iterating).
This approach does have it's drawbacks though, such as rapidly fading into irrelevance and obscurity given the ever-changing landscape of the study environment. It is of course your prerogative to disregard research as you see fit, but hopefully we can agree that this isn't bad science (at least not on that basis), even if you find the results uninteresting.
This approach does have it's drawbacks though, such as rapidly fading into irrelevance and obscurity given the ever-changing landscape of the study environment. It is of course your prerogative to disregard research as you see fit, but hopefully we can agree that this isn't bad science (at least not on that basis), even if you find the results uninteresting.