Yes they did, very explicitly. Early Christian writings about the sins and evils of the world are full of condemnations of war, violence, gladiatorial games, and the like.

Here's an example from St. Cyprian of Carthage (first half of the 3rd century):

>For a brief space conceive yourself to be transported to one of the loftiest peaks of some inaccessible mountain, thence gaze on the appearances of things lying below you, and with eyes turned in various directions look upon the eddies of the billowy world, while you yourself are removed from earthly contacts — you will at once begin to feel compassion for the world, and with self-recollection and increasing gratitude to God, you will rejoice with all the greater joy that you have escaped it. Consider the roads blocked up by robbers, the seas beset with pirates, wars scattered all over the earth with the bloody horror of camps. The whole world is wet with mutual blood; and murder, which in the case of an individual is admitted to be a crime, is called a virtue when it is committed wholesale. Impunity is claimed for the wicked deeds, not on the plea that they are guiltless, but because the cruelty is perpetrated on a grand scale.

>And now, if you turn your eyes and your regards to the cities themselves, you will behold a concourse more fraught with sadness than any solitude. The gladiatorial games are prepared, that blood may gladden the lust of cruel eyes. The body is fed up with stronger food, and the vigorous mass of limbs is enriched with brawn and muscle, that the wretch fattened for punishment may die a harder death. Man is slaughtered that man may be gratified, and the skill that is best able to kill is an exercise and an art. Crime is not only committed, but it is taught. What can be said more inhuman — what more repulsive? Training is undergone to acquire the power to murder, and the achievement of murder is its glory.

To our modern ears, "killing people for sport is evil and disgusting" sounds like common sense, and something so unremarkable that we probably pay no attention to it when reading it on a page. But ancient Romans did not think so. This was a pretty shocking thing for a Roman to write.

What we call "religious persecution" was done by absolutely everyone everywhere in the world until about the 18th century (and even then, it was only in the 20th century that the majority of countries stopped doing it).

This is because all adherents of all religions agreed that it was a matter of public interest to ensure that the right gods were worshiped, and worshiped properly. If your city didn't worship the right gods, or didn't worship them correctly, they might decide to smite your city. To allow your neighbor religious freedom seemed as absurd as allowing your neighbor to set his house on fire - the fire might spread to your house, so you can't do that.

The modern idea of religious freedom only became conceivable once people basically stopped believing that God or the gods intervened in the world very much. That's why the first supporters of religious freedom were Deists (people who believed in a distant, non-interventionist God).

Or proof of the precise opposite, because their laws would count as extremely cruel by our standards.

One of the new ideas that Christianity introduced to the Mediterranean world was the idea of a common humanity, the idea that there are some rules that should apply to all people. Granted, these rules were very bare-bones things like "murder is bad no matter who you're murdering", but the point is that polytheists didn't think that murdering barbarians was morally problematic. In fact, murdering barbarians was heroic. Caesar brags about how many civilians he killed in Gaul - it was considered praiseworthy, and Roman generals almost certainly exaggerated their death toll to make themselves seem more glorious.

Today, modern propaganda is all about denying your atrocities, not exaggerating them. That is moral progress, even though atrocities still happen.

Sure, but that's the only similarity.

In monotheistic religions, God wants you to be good, and offers a definition of what "good" means. Monotheistic religions generally come with a philosophy attached to them.

In polytheistic religions, different gods want different things from you and those demands can be contradictory (something that appeases one god may anger another god). Generally, the demands of polytheistic gods are linked to their domains rather than morality. The god of war usually wants you to murder your enemies in spectacular fashion, for example.

As someone else said, one of the reasons why philosophy flourished in Classical Greece was because their religion didn't really say anything about what was good and what was evil, so people started debating that.

To vastly oversimplify:

The gods are powerful and you are afraid of what they might do.

So, you want to make sure you don't piss off the gods, and if possible you want to appease them and persuade them to help you. The priests have special knowledge about what will piss off or appease the gods, and special abilities to communicate with the gods and make sure the gods notice you when you try to appease them (because these gods are not omniscient; they might fail to notice things).

So as you can see, there is little connection between morality and religious belief/worship in this system. The gods aren't good, they are powerful. The gods also don't necessarily want or expect you to be good - they want you to do the things they like.