Well for me it’s simple, I’ve worked places where we had to destroy food and I just didn’t. I’m lucky enough that it’s always been pretty easy to find another food service job, and I’ve told any managers that I think food waste is the only true sin, and I’m willing to lose my job over it. I know not everyone can afford to walk away from a job, but all of my managers(in two countries) have thus far found a way to look the other way. Your middle manager almost certainly doesn’t want food to be wasted either, so if you tell them it’s a moral issue, that gives them plausible deniability for not destroying it.