This engineering concept of tolerance always seemed to correspond well with its general definition elsewhere. Namely, it was usually acknowledged that nobody is perfect, that it's unreasonable to expect absolute adherence to codes of conduct, so let's cut each other a little slack now and then.
Lately, however, lots of folks are referring to tolerance as if it means that we can no longer hold to any standards at all, that any behavior must be accepted and even approved. Surely such a definition bears no similarity to its original meaning.
If a car manufacturer were to adopt such a definition of tolerance, their vehicles wouldn't run very well. I doubt that you'd even be able to drive them from the dealer's parking lot.