Are you familiar with the multiple comparisons problem[1]? The problem is that in any sufficiently rich dataset, you can find something unusual-looking, and if you're not straightforward about how much digging you had to do to find it, it will look much more special than it actually is. So if a benefit is found by chance, that's fine, but it should only motivate further research which specifically look for that effect.
> but it should only motivate further research which specifically look for that effect
Indeed. But this doesn't disqualify looking for "something" as a valid and useful method of research to be a stage of the whole research chain. That ought to be allowed although research papers produced this way should make this clear.
[1] https://en.wikipedia.org/wiki/Multiple_comparisons_problem