guess what, it's still offline for DCMA.
I don't think anyone will actually go through the expenses to go to court over a code snippet on Github, unless they're particularly principled, wealthy, and retired and I think Hackerrank will definitely try to send their in their legal team.
By just filing a counter notice, you're also doxing yourself to people who clearly have no interest in following the law.
Github seems to have processed the DMCA counter notice but the content is still offline. From that I gather that Hackerrank filed a lawsuit or the counter notice was retracted somehow, or Github is violating the DMCA by keeping the content offline.
Not quite. The obligation of the service provider when they receive a counter-notice is to inform the person who filed the original notice, and give them 10-14 days to file a court order to block the content. If they don't get that court order in that time, the service provider must put the content back up or risk losing their DMCA safe harbor.
At worst, you can try to exercise the controls in the EULA that your victims agreed to, but this sounds like abuse of the legal system.