The Dark Ages are most certainly a black eye on Christianity, the losses during that time can not be calculated properly. That time period is a testament of what the world looked like when Christianity was in command. Also, I have to disagree with those saying biblical contradictions aren't a good thing to bring up. For instance, my favorite thing to bring up with a Christian specifically is that, if Evolution is true, it would imply that the events that lead to biological life in Genesis (Adam & Eve) is bullshit. From my experience, if a Christian keeps wanting to point to the bible, then the bible must be called into question at some point.
If the hypothetical idea of an afterlife means more to you than the objectively true reality we all share, then you deserve no respect.