So if there is not much benefit yet there is usage of the third-party program then there would not be any reason to lift its restriction. That said, the only way that we know you use a fog click detector is because you were honest about it, and any policy based on honesty doesn't work; although that shouldn't really affect whether or not we allow fog click detectors in the first place, just whether or not we ban for it.
An ingame fogclick program is often the only way to catch maphackers (i.e. it took me 4-5 game of playing with gynecologist to get suspicious that he maphacks and only because my detector went off). If ENT is actually dedicated to ridding itself of maphackers like many of the other bots, it will allow and encourage everyone to use a fogclick detector.
Well tl;dr if we support fog click detector exclusively then maphacking would become MORE prevalent because of simple switch to safeclick programs. If a player doesn't show suspicious activity when they are maphacking, then they can easily use a safeclick program and be undetectable. However this is simply not true, it is always possible to notice behavior; if there is no such behavior then the player is not getting anything out of maphacking.