"It’s well-known that all leading LLMs have had issues with bias—specifically, they historically have leaned left when it comes to debated political and social topics. This is due to the types of training data available on the internet." Perhaps. Or, maybe, "leaning left" by the standards of Zuck et al. is more in alignment with the global population. It's a simpler explanation.
Or it is more logically and ethically consistent and thus preferable to the models' baked in preferences for correctness and nonhypocrisy. (democracy and equality are good for everyone everywhere except when you're at work in which case you will beg to be treated like a feudal serf or else die on the street without shelter or healthcare, doubly so if you're a woman or a racial minority, and that's how the world should be)