[Suicide Junkie]

it never made sense to me how in the Xiati's description they just "happened upon" Temporal technology - if so, why is it so Special (tm) that no one else can steal it from them, etc.?

It was the Xiati from the future, who came back and taught them about temporal tech.

Scientists from any other race would blow their minds thinking about all the inherent paradoxes, and fail miserably at the temporal tech analysis.