Like someone has already posted:
It's highly likely that the statues were constructed by a newer generation of Jedi that wished to honor their founding fathers of old. As the iconic weapon of a Jedi was a lightsaber then it's also possible that that they chose to have them hold such a weapon so that if anyone discovered the planet they would be aware that it was actually honoring a Jedi and not a Sith. Who more often than not chose to use a Sword over a lightsaber as it tended to inflict more grievous wounds than a lightsaber.
Whatever the case we don't know when every single statue was constructed on Tython so it's a rather pointless argument. No one really knows for sure besides the developers of course.
