Do all Islamic rulings ultimately "make sense"

Answer

It depends what is meant by "makes sense." If looking for the jurisprudential logic (the 'illah) behind every ruling, this is known for some rulings (ma'qul al-ma'na, e.g. intoxicants are haram because they cloud the mind) but not for others (ghayr ma'qul al-ma'na, e.g. why Fajr is two rak'ahs and Zuhr is four) -- yet it isn't proper to call the second category "not making sense," since we can still find practical, spiritual, or psychological wisdoms (hikam) for those rulings. At a broader metaphysical level, every ruling makes sense once the relationship between man and Allah, and the purpose of human existence, is understood -- that relationship is itself the sensible premise, even where the "sense" ultimately reduces to obedience. To make sense, in short, is to move from premise to conclusion without a logical absurdity, and no ruling in Islam fails to do that once its premise is understood.