I think that it is more about working around limitations, a TOS saying "I can do whatever I want, you cannot" might not hold on the basis of being too general,

I think that it is more about working around limitations, a TOS saying "I can do whatever I want, you cannot" might not hold on the basis of being too general, so you list all the areas where you can do whatever you want. Also if by law the user has some rights sometimes you might want to be careful to avoid contradicting them. Overall the cost of adding another paragraph is fixed and negligible and the possible gain in loss prevention is considerable