Bethesda is making millions of PC copies of the game that are sold because of mods. So it is a symbiotic relationship between nexus and Bethesda their Steam Workshop experiment ended badly. So...
Nexus & Bethesda isn't mad at TTW we aren't mad at Nexus/Bethesda. Bethesdas policy is not to allow any content of other games (if Bethesda or not) released in mods (when the publisher doesn't explicitly allow it Stalker is a positive example here).
TTW fulfills this requirement.
That TTW isn't on Nexus has the reason that other modmaker could think they can now freely use FO3 assets on Nexus for NV because of the simple existence of TTW. Yeah its not intelligent of them but it will happen (it already does constantly but not because of TTW).