I would even argue that in the West, there are industries where copying isn't really frowned upon. My wife's an art design major and background before moving into programming. Copying is not uncommon. Hell, I can look to the auto industry for lots of copycatting going on. If anything, the frowning seems more circumstantial; we frown on copying with things more like homework or Big Co copying the little guy. Of course, then we get universities that don't frown on blatant copying; sister-in-law had one student working on her PhD and copied straight out of one of SIL's published books. The school let it slide.
As to ethics, yes, I do think the copying here is more an ethical issue than a legal one, honestly. That gets us into an interesting situation. In general, it is preferred to receive approval from the original set designer if you're trying to run a previously-run colorway. However, we get ambiguous in these things. While it might be claimed to be unethical to copy without permission, it's also problematic to simply sit on a set and grant no permission despite doing nothing. At some point, I feel that it's simply a matter of best effort; if you try and no permission is given but nothing is being done with the set, it's open season. Similarly, what happens with abandoned set colorways, etc. that were given only mockups but have yet to be produced? I'd also argue that, at some point, those are free reign for someone else to take up as well. If the original creator comes back, the new creator can always back down but we've seen many designs simply abandoned for many reasons.