I am not an expert on LLMs, so I may be misunderstanding here. But doesn't this research basically imply one of two things?

1. LLMs are not really capable of "being controlled" in the sense of saying, "I want you to hold certain views about the world and logically extrapolate your viewpoints from there." Rather, they differ in political biases because the content they are trained on differs.

...or...

2. LLMs are capable of being controlled in that sense, but their owners are deliberately pushing the scales in one direction or another for their own aims.