Contract law, due to the user not abiding by the license agreement, is more relevant than copyright infringement. Apple gives the OS away freely and there's no copying act that you do for yourself that would be infringing (e.g. copy the OS to a Mackintosh's drive and you're still okay), it's only the use of the OS which is a problem and that's not a copyright problem, it's a license problem.
In other words, you're violating Apples copyright by running MacOS on a Hackintosh, and Apple is well within their rights to sue you for damages. Defending these types of lawsuits are expensive.
IMHO they did the copyright, because they don't want someone to put a stamp "MacOS X - tested" or something on their hardware.
Does Apple really document how to break their EULA on their website: https://support.apple.com/en-us/HT205041
"Removing or installing memory
You should not manually upgrade or replace the memory in these Mac mini models. Instead, contact an Apple Authorized Service Provider or Apple Retail Store to install memory for you."
Or the other way around. If I take the HDD of a MacBook Pro and put it on my Hackintosh, am I violating the EULA?
So I think the line is so thin and you can argue about anything on that topic.