Then the question should've been "is it ok to perform experiments on uninformed participants" or "would it have been ok if they splashed water instead".
The doesn't try to explicitly link their question to the article and instead its prose is a hypothetical.
Instead, the guy ask if its ok to splash water. I can't think of any reason why splashing water would be the line at which its no longer ok to have an experiment. I certainly can see uninformedness being a reason not to have an experiment but that's a different question and so it would get a different answer.
You should deploy critical thinking skills. Splashing water on someone is in fact assault (or more accurately battery).
But that's besides the point, which isn't very hard to understand. The point is that just because a substance or act doesn't seem harmful _to you_, doesn't mean it doesn't violate someone's rights.
The doesn't try to explicitly link their question to the article and instead its prose is a hypothetical.
Instead, the guy ask if its ok to splash water. I can't think of any reason why splashing water would be the line at which its no longer ok to have an experiment. I certainly can see uninformedness being a reason not to have an experiment but that's a different question and so it would get a different answer.