> Recent technological advancements have empowered nonhuman entities, such as virtual assistants and humanoid robots, to simulate human intelligence and behavior.
In the paper, "socio-emotional capability" is serving as a behavioral/operational label. Specifically, the ability to understand, express, and respond to emotions. It's used to study perceptions and spillovers. That's it.
The authors manipulate perceived socio-emotional behavior and measure how that shifts human judgments and treatment of others.
Whether that behavior is "illusory" or phenomenally real is orthogonal to the research scope and doesn’t change the results. But regardless, as I said, they quite literally said "simulate", so you should still be satisfied.
It is the ability of the agent to emulate these social capacities that leads users to attribute human-like minds. There is no assertion whatsoever that the agents have a mind, but that their behavior leads some people to that conclusion. It’s in your own example.
In brief, the paper consistently but implicitly regards these tools as having at least minimal socio-emotional capabilities, and that the problem is humans perceiving them as having higher levels.