This kind of discussion usually ends with historians trying to explain things about the roman hostility and violence over christians, and christians becoming really defensive, slightly offended, and absolutely skeptical of what is being told. In that sense, roman religion is highly alien to our definition of religion, and that is, naturally, hard to understand if one is too connected with modern religious dogmas, culture, and religious thought, which is completely natural. We can go down this road, I am just saying the most probable outcome.
Martyrdom wasn't seen as a possible necessity, it was craved for, at least by a not so smal number of early christians.
If we compare Rome to the Middle and Modern Ages, yes, they were amazingly tolerant. By our standards? No, obviously not.