As I already mentioned, I'm not talking about situations where your windshield is suddenly obstructed since that situation is especially rare, so if you can see clearly enough to drive safely in the first place, then you can see clearly enough to evaluate your surroundings.
It seems obvious to me that spraying your windshield with soap obstructs your view for a moment, but I'll admit that the occlusion is likely variable depending on the make and model.
I stand by the claim that it is safer to not use your wiper fluid while moving when possible. If you disagree, that's okay. It's a pretty minor point - there are many other driving habits that are far worse in my opinion.