That thread needs to be stickied and all threads ignoring it be destroyed. Seriously, for a supposedly left-leaning forum you see the most blindly imperialist/colonialist people around here who thinks all non-colonizing people are inferior and irrelevant. Simple fact of the matter is, if a boat full of Romans lands in America randomly, they either live out a meagre existence in the middle of nowhere, die from disease or starvation or exposure or anything, or get brutally killed by the natives. They are not going to create an empire simply by virtue of being from Europe.
This post needs to be put somewhere on the AH list of Easily Forgotten Things About Real History, along with this thread being stickied.
Its one thing for the argument to be made that Europeans, such as the Romans, can conquer the natives. But there's a difference you couldn't fill with an ocean between a project of Roman expansion into America and Random Romans Arrive, Now What?
And even the former needs to be beaten over the head by the Native Inhabitants experts, apparently.