Rashi says that Tzora'as comes from talking Lashon Hara. It is white, perhaps since it shows a person’s feelings of superiority, since “white” means “the pure good guy” who has nothing wrong with him. Normal flesh is a mix and not perfectly white, since we should all realize that we aren’t perfect.
A human is a cross between a Neshama and a Guf (physical body). Actually, being white is a Chisaron. It means you think you’re perfect and everyone else makes mistakes. Like Lavan, who ran after Yaakov and was constantly reprimanding him; and being concerned about how Yaakov treats his daughters. This was ludicrous, since from their perspective they felt he treated them like: נָכְּרִּ יוֹת ויצא לא טו strangers. He lived in a myth: “I’m white!” Indeed, dead people belong white, since their Yetzer Hara is dead, and they have no more Tachlis (and a Metzora is considered like he’s dead).
When a person gets white Tzora'as, it’s like a message telling him: “You think you’re a “Lavan” whose name is “Mr. White” because he thinks he’s perfect and pure, and everyone else has to get his Mussar so they’ll straighten out”. Notice how the Torah is always pointing out the mistakes and failures of Yaakov and Moshe and our greatest Tzaddikim. We are all human flesh people, and not white Lavan’s. In Novardok they said: “The Pope never sins. We do!”
