They absolutely were the values, albeit a subset of them - of Greco-Roman culture, atleast by the 1st century BC. Christianity itself is a Hellenic (Greco-Roman, remember the Romans were Hellenophiles) religion, derived from these values and understanding and synthesized with the Israelite prophecy. Christianity would have never been integrated into the Empire without the foundations already being there. It took a couple centuries for the Roman public at large to understand it - the problems early on were a lack of communication and understanding - Christianity revealed a common truth that underpinned all gods, but for the public to actually digest and understand this was no easy task as it was a total reformation, a reordering without replacing, of their worldview.
It's important to understand that all 'gods' were simply (or maybe not so simply) representations of immaterial transcendent truths. These ranged from the crudest form, which was nature worship as seen in the Druidic Celts and the crude fertility gods worshipped by the Phoenicians (remember their worldview was largely produce-consume), to the most refined form being the Greco-Roman gods such as Apollo, Jupiter, Saturn, Venus etc. So it of course made sense that they recognized this in competing civilizations.
The concept of atheism didn't exist at this time. You are correct that they viewed Judaism and initially Christianity as exclusive religions, which they didn't like, until the worldview was actually understood centuries later.
Lol the concept of atheism certainly existed, the word just didn’t. Socrates was charged with and put to death for not believing in the gods several hundred years before the time we are discussing. But as I already explained, the concept was slightly different from a polytheistic perspective.
I meant that the jewish and christian religions were exclusionary in that they precluded the existence of all other gods. This is still how both religions work, nothing was explained away. Christianity and Judaism were both totally incompatible with the Roman mode of thought. It took hundreds of years, thousands of crucified christians and a massively declining empire to bridge the gap.
Kant was a Christian, which obviously professes a universal morality which can be discovered. His view is simply the Christian view, the truth that Jesus is Lord and only through a personal relationship with Him can we arrive at the Father is a truth revealed by contemplation (reasoning) and revelation/epiphany.
Every person who isn't an imbecile believes in a universal morality. The question then becomes, which? Islam, Christianity, and Judaism are all competing understandings of universal morality. Jews believe it is moral to treat people outside their tribe as cattle and that they should be worshipped by the goyim, Muslims believe it is moral to treat women as cattle, etc. All claim universal morality.
That’s not right at all. Kant did not believe that revelation/epiphany was needed to uncover the universal morality. He said pure logic is the only thing you need to do it, no knowledge of Christ required. He also believed that prayer and miracles are the result of ignorant superstition, so whether or not he was a Christian, he most certainly was not the sort of Christian you just painted him as.
Jews don’t believe they should be worshipped… the Noahide laws ban this explicitly.