The definition of a loophole is taking advantage of an abiguity in the wording of a law to get around complying with the law.
This is only applicable to man made laws which will always have some abiguity.
Hashem’s Torah is perfect – there is no ambiguity. The Torah itself says (either Torah Shebiksav or Torah Shebaal Peh) that in certain cases one may do a melacha – for example in the case of pikuach nefesh one MUST do melacha to save a life. Its not a loohole, its what Hashem wants us to do. Another example that probably bothers you is that one may move certain types of muktza (a pen for example) if you need the place where its located. This again is not a loophole – its not that someone forgot to include that case in the law – instead its the will of the Torah that it be allowed.
Similarly, the Torah includes rules of chinuch. At age 2 when a child doesn’t understand the concept of shabbos and melacha there is no obligation to stop him from doing a melacha. (You can’t tell him outright to do it). Putting a chair there for him to turn on the light? hmmm… I suggest asking a qualified posek on that one.
The bottom line is that shabbos is not about blindly not doing melacha – its about doing the will of Hashem which includes all the rules of when a melacha can and cannot be done.