Beta-level simulations were sophisticated computer programs designed to mimic a person in appearance, mannerisms, and thought-patterns. While capable of successfully impersonating a human mind down to their most minute idiosyncrasies, they were not in fact self-aware -- they were just near-perfect imitations of life. As such, they enjoyed no legal rights or protections.
In Yellowstone society, and presumably other Demarchies, it was considered a most egregious social faux pas to allow someone to believe a beta-level simulation was in fact alpha-level.