ngl, guy who brags about killing a million people and enslaving another million sounds like a piece of shit.

If saying "I won over a large number of enemies" is all that it takes to count as a piece of shit, I have really bad news about the Gauls for You.

Even if he’s lying, he still wanted to be seen as a genocidal oppressor of holocaustic scale.

That's not even close to the message, especially considering the rest of the Commentarii.

Any society which would approve of such supposed actions is evil.

... how do You think Gallic societies reacted to their leaders murdering and enslaving others?

I stand with the barbarians.

Of course. What's a little human sacrifice and executing the slowest member of each tribe for 'disloyalty' between friends?

This is not to assert moral superiority of Rome over the Gauls, only to point out that extreme violence and its celebration are not particularly Roman. They're simply pre-modern.