That feels like the opposite of being true. Juniors have, by definition, little experience - the LLM is effectively smarter than them and much better at programming, so they're going to be learning programming skills from LLMs, all while futzing about not sure what they're trying to express.

People with many years or even decades of hands-on programming experience, have the deep understanding and tacit knowledge that allows them to tell LLMs clearly what they want, quickly evaluate generated code, guide the LLM out of any rut or rabbit hole it dug itself into, and generally are able to wield LLMs as DWIM tools - because again, unlike juniors, they actually know what they mean.