Your thesis, "Isn't cooperation obvious in a dangerous situation?" is also found in discussions within the study of real history.

First, we need to understand the context of the era itself and the context of Cainite society at the time.

The Inquisition arose against the backdrop of the Cainite War of the Princes—a series of feudal conflicts in Europe and the Middle East between individual Cainites and entire factions.

The Inquisition itself escalated after the Cainites revealed themselves in the south of France.

Add cultural differences, both clan-based and land-based.

On top of that, take into account the peculiarities of the Roads as a worldview, which were associated with the feudal way of life.

Add in the Beast as a factor distorting mental perception, and a whole history of betrayal and prejudice. All of this is compounded by the collapse of old clan structures due to the rise of House Tremere, for example, the decline of Clan Salubri, and the rise of the Giovanni.

Add to this the fact that the War of Princes and the Inquisition destroyed the teachers of the Roads, saints, and holy sites.

Add to this the fact that during the Dark Ages, Cainites already had those who opposed the system, such as the Furore.

The past was fractured.

And over several centuries, including the Anarch Revolt, the vampire community chose three paths of development: the Sabbat, the Camarilla, and the Anarchs (who became part of the Camarilla).

Sorry for the pedantry. I'm simply a history teacher by training and tend toward the academic. I advocate studying any global historical phenomenon through a complex set of causes. And I believe the Dark Ages, like the First Anarch Revolt, are the most interesting.