That was the lightsaber Anakin Skywalker had when he was a Jedi Knight, it stuck with him even when he became Darth Vader before he lost it. When Luke acquired it, even Vader noticed something about it(In the comics). The fact it kept ending up in Force User hands was not a coincidence, and saying it didn't call to her when you literally hear it calling to her and no one else is just... well, no offense, ignorant.
How else would explain it?
How else would explain it?