The “slander” (not a legally accurate use of the term) referred to the media campaign, which was effective around 2010-12 and has lingering effects, as seen here.
You're trying to dismiss a series of technical reports on Toyota's software engineering defects - reports that directly acknowledge that it's impossible to prove causality beyond reasonable doubt because of the software engineering defects - on the basis of their similarity to an unrelated report from 1989, and because you "smell a rat".
