The problem with Scratch is it is a form of online media that can be used by little kids. The problem with little kids is that they are ignorant, and these ignorant kids don't understand copyright and intellectual property. So when Scratch goes around appealing to kids while also telling people to credit properly, these ignorant kids are not going to follow the rules and just steal stuff, especially Undertale sprites. Can you really expect some kid who is just having fun putting together these Undertale projects using stuff he found online to care about who made the stuff he put into the project? No.
Now this is a problem all in its own right, but then when people who do know why credit is important come across these projects, they start telling them to credit, and when the little kid still doesn't care, they start getting harassed and bullied by other people calling them "garbage" and telling people to mass report them. This is a dilemma, because while I feel crediting is important when using someone else's work, but I also feel that some kids on this website are being attacked for not knowing better by people who care way to much about being as harsh as possible to these kids.