What I said some weeks ago was that early Christianity was able to nicely ride on the back of the Roman empire....using its "intactness/contiguity", its infrastructure, road system, system of commerce/exchange/trade routes, language, preference for order/organization/law, its respect for the intellect to spread.

Many people have no clue why Christianity spread so quickly PARTICULARLY in an environment of persecution. 

And so they'd rather just engage in brickbat.  And of course this just makes them look small and poorly educated.