Your first reference states that the Planck length isn't the smallest unit of length in standard physics: "The Planck length is sometimes misconceived as the minimum length of space-time, but this is not accepted by conventional physics, as this would require violation or modification of Lorentz symmetry." It then states that alternative theories do allow for a minimum length.

Experimental evidence (the Fermi satellite data discussed in the link in the grandparent comment) seems to support standard physics.