Which would make sense if he considers lightsabers irrelevant to the new teachings of the Jedi, except he still uses that very lightsaber when going against Kylo

Nah, he views lightsabers as irrelevant, and he doesn't use a lightsaber against Kylo. He uses an illusion of a lightsaber, and he doesn't even attack with it. He just dodges and distracts. The lightsaber is nothing more than a symbol to distract Kylo. It's serving the same function as a set of jangling keys.

And he had to have that pacifistic viewpoint, that anti-lightsaber viewpoint, because Abrams put him on an island during a war. The best answer RJ could come up with to that is that he's become a pacifist.