So if someone playing the game is Muslim should he be offended if someone draws a cross?
Since the crusaders murdered thousands of innocents in numerous cities after conquering them.
Should a non-christian be offended also by the cross especially if he has european origins and hence his "ancestors" suffered under the Inquisition?
In general if you WANT to find racism and if you consider a 'symbol' to be evil then you have other issues and problems in real life and no game can solve all of those. If you start nit-picking then you will find a million things that could be considered improper or racist from one group or another and you cannot satisfy all of them but satisfying some of them just makes it feel more unfair.
Unless you are prepared to add to the rules of the game "You are not allowed to bring up in any manner: Religion, race, belief system, core values, political views, wealth levels, family relations, football team preference, basketball team reference" and so on and so forth anything that may cause division, derision or arguements" then in my honest opinion you should not bother with such rules.