@curiousdannii I wasn't the one that handled that flag and I may have marked it helpful instead of decline, but I probably wouldn't have deleted the answer either. If the information it proclaims were actually correct rather than a bunch of baloney, I think it would answer the question. As such it is less of a moderation issue than one for the community to vote on.
BH.SE is a lot less strict about what it means to "answer" a question than C.SE, and unlike there, here saying the premise of the qusetion is all off and coming at it from another angle is totally okay as long as you meet the other criteria for an answer.
BTW @curiousdannii have you ever done any Haskell programming?