Why isn't Luke's lightsaber red?

Question

According to the Ahsoka novel (written by E. K. Johnston), Kyber crystals choose Force users and present themselves to their desired owner, but dark siders don’t experience this same connection to the crystals. The only way the Sith and other dark side Force users can collect kyber crystals is by stealing them or plundering them off the bodies of their fallen foes. Even if a dark sider were to acquire a kyber crystal from a green or blue saber, the act of bending the crystal to their will in a new lightsaber will cause the crystal to “bleed,” turning it red.

Anakin's second lightsaber was used by Vader to amputate Mace Windu, kill dozens padawans at Jedi Temple, slay all Separatist leaders and fight Obi-Wan on Mustafar. After dismembering Anakin in Episode III, Kenobi picked the saber up and 19 years later, he gives Anakin's second lightsaber to Luke and the blade is still blue. Shouldn't it be red now?

Answer 1

Crystals don't change colour while inside a lightsaber

This is something that Pablo Hidalgo seems to get asked on an almost weekly basis on Twitter; here's just one of his many (identical, with slight variations on wording) responses:

@JosuSen after reading about cristals in Ahsoka,does it mean remasterd ROTS would show Anakin killing youngsings with a red lightsaber?

@pablohidalgo no, crystals don't change automatically. It's an exertion of will during the construction of a lightsaber that does it.

For Anakin's lightsaber to turn red, he'd have had to disassemble and reassemble it, forming a new bond with the crystal in the process; obviously he didn't exactly have time for that while right in the middle of Order 66, but presumably he'd have gotten around to it afterwards, if everything had gone according to plan.