I think we are waaaaaaay past the point about arguing about The Spear, considering how many people have jobbed to it by now. It's his finisher, it's credible enough where it'll put anyone down. It looks weak, but hey, it works.
Because by the time Jin met her in the past, she was already dead in the present. Kinda like why Desmond didn't remember meeting Faraday while in the hatch until the present.