When we speak of moral absolutes, we are not making any claims about religion or the origin of moral absolutes. Right now we are simply establishing that we humans universally recognize that some behaviors are always wrong, such as torturing babies or gratuitously murdering innocent people.
Whether one believes this universal code of moral truths was instilled in us by a creator, or evolved in our species, the idea that morality is different for each individual person, group, or time period doesn’t fit reality.