I hope your faith in them will turn out to be justified, but there is clearly a pattern to their behaviour. In a previous takedown reported here just five months ago (https://news.ycombinator.com/item?id=29239594), the takedown was not reversed either; for some projects the takedown was likely legitimate, but for others this was obvious abuse.
The founder states in a comment (https://news.ycombinator.com/item?id=31091354) that "[their] intention with this initiative is to takedown plagiarized code snippets or solutions to company assessments", practically admitting that they are knowingly abusing DMCA systems to execute takedowns of other people's code. They can definitely take down plagiarized code snippets under the DMCA, but they have no right to take down "solutions to company assessments".
