LibTourist-3.0 is replace them of TouristLib, if it is the case I can destroy the directory TouristLib ???

LibTourist-3.0 is the replacement, true, but if an addon uses the older TouristLib, then you still need the older addon. From a coding point of view, any addon that uses the older libs is subject to be rewritten so it can use the newer libs. Some addon authors don't want to take the time, still like the older libs, aren't actively coding, or have stopped playing WoW.

The trouble, from a developer point of view, is the whole rewrite thing, as there is a whole lot more than just a file renaming.