While much of what you say contains truth, I think you are too quick to discount overall company culture. If the processes in one part of the company can get so lax without management correcting it, it's more likely that the same problem exists in every other part of the company as well.
Even if the only part of Lenovo that sucked was the group that decided that the malware was acceptable, that still means the company as a whole can't be trusted -- since from the outside of the company, there's no way to know what groups suck and what groups don't.
However, the reason that I will never again purchase anything made by Lenovo is more basic than that: their official response to Superfish was either that they were outright lying or that they were seriously incompetent. Either way, they proved to be a company that you can't trust -- even if there are groups within the company that are trustworthy.