R602.5 It actually says you can use 2x3's on 24" centers in a non-loadbearing wall.
2x4's at 24" OC, is actually enough for some loadbearing walls (supporting one floor only, or roof & ceiling only).
No offense, but... like... none of that is true.
There's a bunch of code sections that specifically apply to non-loadbeaing walls. Lumber still has to be a certain grade; there's still a maximum you can notch the studs; it still needs a top plate; it still needs fireblocking; etc.
As for drywall & tile, the code provisions on interior wall coverings, still apply. There's nothing in there that distinguishes between load-bearing & non-load-bearing walls, it all applies to all walls.