Don't look at trimming what should have been left off at the factory as butchery. Consider it selective alteration--an art form like fine tailoring. After all, butchers a.k.a meat cutters are no longer considered degraded prolls but are now professional tech workers who do their art in meat (no doubt there is a less offensive PC term).

Maybe pack trimming could be defined as: backpacks upscaled through creative high end remodeling. We could refer to these techies by the acronym butcher.