This is a gamer joke, pure and simple. The ten foot pole first appeared in the now venerable Dungeons & Dragons as an item of miscellaneous equipment. It just seemed like an odd thing for a group of adventurers to carry around, and yet in the early days of roleplaying we all did so, simply because it was listed on the equipment list, so presumably had a good use.

And it was amazing the improvised uses we came up with for it. Poking piles of bones to make sure they were really dead, setting off traps without getting too close, probing murky water for holes or monsters, etc, etc. But I'm still not sure what a ten foot pole is supposed to be used for, or how one conveniently carries such a thing. I doubt any groups of knights or crusaders really carried around a ten foot pole with them, "just in case".

Of course, the other use of a ten foot pole is refusing to touch things with it. But that hardly seems a compelling reason to carry one around.