on lammps 3feb version
rotate keyword doesn't affect anything
on 5 may version it's works and rotate of 5 rad.
example of start script
units metal
boundary s s p
atom_style atomic
dimension 2
variable f equal 5
lattice hex 2.80
region box block -100 100 -50 50 -1 1 units box
create_box 2 box
region target block -100 100 0 20 -1 1 units box rotate v_f -100 0 0 0 0 1
create_atoms 2 region target