AFAIK, scholars generally consider it to be at least broadly true, which is sufficient.
That you criticise others for barbaric practices proves my point. They didn't find them barbaric, but admirable.
Caesar was the archetypal great man who would be an aspirational figure for most males in such a society. The man who can kill and enslave his foes and gain personal and tribal glory is praiseworthy.
What I said was:
This is a neutral description.
They are alien, and I'm absolutely certain that few would find them preferable.
How do you feel about those funeral rituals? Relatable? Familiar? Something you'd like to see make a return?
People are a product of their time and place. Pretty much all cultures have things that are admirable and things that are objectionable.
I remember watching a programme about a British man in Afghanistan who was arrested, his Afghan guide insisted he must be incarcerated too until the man was freed as he had been his guest and was thus responsible for his well being.
This is the same honour culture than might make the same person kill his sister for being raped or for not wearing a Burkha.
The same Christian evangelical zeal that drove the abolitionist movement that led to the banning of the slave trade drove aspects of colonialism and the desire to Christianise "savages".
How these pagan societies would have developed over time, no one knows, but the fact remains they are completely alien to our modern sensibilities, even though we can try to understand why they had value in their time and place.
Sanitised versions based on our own modern values are not the historical reality though.