I can't fathom why fictional tracks are such a huge turn-off for "hardcore" racing sim fans. I agree with what
@TheElbows said about being able to drive real tracks from motorsports, but that does not preclude the existence of fictional tracks in the roster.
Numerous real world racetracks are tedious or boring, especially in today's safety-minded motorsports culture. Wide runoffs, flat ground, wide surfaces, inorganic chicanes, and other related features undermine the thrill and enjoyment of lapping a circuit in consequence for accommodating driver safety or spectator views, and they're unnecessary in a simulator with no actual wrecks or crowds.
That's not a reason to exclude such real world tracks, but I think a game suffers when it has nothing else to offer. Historic tracks that aren't so safety-minded are a good compromise.
Personally, I've always preferred road-inspired fictional tracks in racing games, because the freedom in design and topography allows for creative tracks that offer the best possible driving experience (and scenery). Although the "hardcore" cry that such tracks belong in an "arcade" racing game, a proper physics simulation is ideal for wringing the most out of an exciting fantasy road course.
I'll like to see what SMS come up with for the touge discipline in PCARS2. I'm hoping for something closer to a tarmac rally stage than the freeway-sized ribbon of Forza's Fujimi Kaido.