why would you report my answer?

The same people you see asking the idiotic trolling questions also have the power to report your answers, so it's a wonder the whole thing runs as well as it does. Don't let it bother you. It happens.

Someone might do that if your advice were seen as being dismissive or arrogant, but such advice can be both well-intentioned and valuable if the question is a serious one that deals with health, for example.