I would compare the apple hardware agreement they violated to software agreements which forbid analysis, reverse engineering, or even benchmarking (there's some notable enterprisey software which forbids conducting benchmarks and sharing the results).
I would not condone redistributing copies of software or significant portions thereof in a way which violates the license, whether it be a copyleft license or a commercial license. If apple distributed gerber files for the PCB of the new hardware device, or original CAD schematics it uses to manufacture parts, under some license, I'd also want the terms of the distribution of that to be respected.
But this is something of a different nature. It's taking hardware apart and seeing what's inside and sharing that researched information rather freely on the internet. This is not a copy of source code or hardware schematic. This is learned information. It's not vandalism - there is no expectation that any dev kits be returned, each recipient can use theirs exclusively. This is something everyone everywhere should always have the right to do. And iFixit does, more or less.
What sucks is that Apple can retaliate by exerting their complete and arbitrary control over what software millions of people are permitted to run on their own devices. That's really messed up. This is just one more great example, in case you don't understand yet.