Well Steve, we can look back and say, why did the Romans not write about Christ ( if they did,nt that is ), and there could be any number of reasons for this, including their not recording every Jew or other nationality that caused a problem for a roman governor. I,m sure Pilate would like to have forgotten it.   Having no extant record from the exact time is hardly a strong argument again him, especially as it is only a matter of decades after that there is record of him and his followers.   But, granted, not a bad shot, for an argument from silence, or as you insist, a lack of evidence, exactly contemporary with Jesus,