Copyright is a very though cookie*. Laws differ significantly from country to country. Your expected to follow the law in your country no matter what the original author worked under. On top of that stackexchange needs to operate under US jurisdiction.
It is not our job to enforce copyright. You may want to read
In essence the DCMA complaint is for this purpose. You can do whatever you like but you have no obligation to do anything about this matter. We do not even know if it is violating any copyright.
* for example code snippets on stackexchange rarely get copyright in my jurisdiction as they do not qualify as copyrightable works unless they are significant codebases (30 lines rarely is a significant codebase). On the other hand publishers have natural moral rights to whatever they write, so I will need to attribute that code no matter what the license of stackexchange says. If its copyrightable it may be copyrightable as a textual work in which case i can obtain a license form the appropriate local trade organization, on your behalf. After having done this you have no copyright claim I've handled my end. Unfortunately the trade organization does not have to pay you until your account has a significant sum of money or your a member.
But if I wan't to use my code in US i better follow the copyright holders wishes anyway. Which I do for moral reasons. If you want to know more about my local laws can try to google translate this article but im afraid it wont work out very well.
PS: None of the exams ive ever made have any copyright protection per see. Which is why its standard that student unions keep databases of past exams where I am.
DISCLAIMER I am not a copyright lawyer and certainly not your copyright lawyer.