To take another example, I was recently reading Suetonius' Twelve Caesars and found out where Martin got the inspiration for the part about baby Aegon's head being bashed in against a wall: when the Praetorian Guard murdered Roman emperor Caligula and then his wife, supposedly their 3-year old Julia Drusilla managed to bite one of them, and suffered that same fate. (Similarly, Martin's characters certainly have plenty of justification to rise up against their lawful sovereign - but then taint their hands with some horrible crimes.)

For one of Erikson's bloodiest scenes - the one involving mass crucifixion - there is also an obvious source of inspiration, in the actions of the Romans after they finally managed to put down Spartacus' rebellion. It would perhaps make more sense to accuse them of unoriginality in their extreme violence, than of going beyond reality.

And regarding prostitution, I'd actually be inclined to say fantasy has a tendency of romanticizing it and presenting it rosier than it generally was in history.

Lastly, I think it should be pointed out that what happened in the Democratic Republic of Congo and to a lesser extent in some surrounding countries in the past fifteen or so years exceeds very nearly everything I've ever read in a fantasy novel, I'll spare you the details.