It was somewhere outside Barstow when wrote:

This won't work on the 'standard' galvanised wire used as the
tensioner for chain link fences, there's no way you'll stretch it by
pulling on it 'by hand'.

Of course it will - they're fencing pliers, they have a curved head so
you can use it as a fulcrum and use the leverage of the long handles
to get enough force to strain the wire.

A "straight pull" won't do it, admittedly.