“You should have heard of this” is always an (implicit) criticism of whoever you should have heard it from (e.g. your parents, teachers, doctor, pastor, boss, n

“You should have heard of this” is always an (implicit) criticism of whoever you should have heard it from (e.g. your parents, teachers, doctor, pastor, boss, news media, or the society at large), not a criticism of you yourself. But here the intended meaning is more along the lines of “it is unfortunate that we all collectively pay so much attention to Bill & Steve but don’t also remember and celebrate Dan and Bob”.