This is true. In 3.x, the uses of and DCs for skills were much more prescribed.This statement applies equally to skills in 5e, the DM rules on basically everything related to using a skill, from when you can use it, to how difficult it is, to what happens when you succeed/fail.
The secondary skill table is basically your background where you explain to the DM why you think it would allow/help you do something, and the NWP were the skills and they'd agree or not.

