A nonprimitive pair is not an ordinary slope

The coordinates $(2,0)$ have greatest common divisor $2$, so they are not primitive. By [F1], they therefore do not represent an ordinary slope or the meridian class of an ordinary smooth filling. The primitive pair on the same ray is $(1,0)$.

Write $(2,0)=2(1,0)$, so the radial factor is $r=2$. If a hyperbolic deformation realizes this generalized parameter, [F1] gives its completion cone angle $2\pi \mathrm{/}2=\pi$, rather than the full angle $2\pi$ of an ordinary smooth filling. No realization is asserted or needed: step 1.1 already supplies a nonzero integral pair that cannot be the primitive meridian class of an ordinary filling, refuting the stated universal claim.