This is indeed true, Tacitus was actually writing during a time of Christian tolerance. It was around this time that Pliny, as governor of Bithanya, wrote a letter to Trajan asking whether or not to punish Christians in his province, to which Trajan replied something along the lines of 'Only punish if they have committed a crime' (this is paraphrased, but you get the idea).
Anyway, I voted for other as wanted Marcus Aurelius the list. According to a book I read on Christianity within the Empire (I cannot recall the title) Marcus Aurelius' Christian persecutions, though not as cruel as those of Diocletian, were more numerous than any other emperor.