I just think it's perfectly ok to talk about how sensitive, say, a camera is, even if you bought it with the intent of photographing smurfs or unicorns but only end up with cat photos (can never have enough of them anyway). An experiment like one of the XENON ones is just sitting there looking for events, and the filtering of those events for the interesting ones only happens later in the process of analysis, so it's perfectly ok to talk about it being very sensitive, and also ok talking about how sensitive it would be to something if some weird thing exists. In the same way you could in principle figure out how sensitive a camera might be to foot high* blue hominids in white hats in certain lighting conditions.
With Verlinde's theory and what it applies to it maybe depends on what you mean by big and small. I'll start by noting that with QM it applies very well to big things too - with the exception it doesn't do gravity. It just turns out to converge on classical mechanics very neatly and you'd be mad to bother doing the calculations on those scales that do converge. Verlinde's theory should likewise converge on general relativity in most conditions where the latter seems to work well and diverge somewhere else (or it's not going to do the job it's been raised for here of dealing with the problematic evidence that otherwise points to dark matter).
GR is known to work very well on solar system scales down to ~centimetre scales (and pulsar studies suggest it works brilliantly in very strong gravity environments too). If it doesn't work well on larger scales then the question is if it doesn't work on those scales simply as a result of length, or as a result of environment. For example, when you get into outer space it's mostly empty - is it density that matters then rather than length scale? From what little I understand it's low densities where Verlinde's ideas become interesting anyway, but there may be other areas too. MOND theories for example kick in at low accelerations instead. The fact that GR seems to work well for pulsars suggest it at least isn't simply big stuff in the sense of large heavy lumps of matter that is where Verlinde's stuff is of interest.
*apologies if smurfs are thought to be a different size to that. Am not a smurfologist unfortunately.