Yes.. there are definitely online-people, and offline-people, or text-async-comm people vs personal-comm-people: for one the one way of communication is more convenient, for others the other, and for some there is barely a difference.

But this is imo fully orthogonal to Juniors not daring to ask questions, and depends on personality, the environment, the mentors, and maybe also the online- or offline-affinity vs the most prevalent tools, but as far as I observed that is the least impacting it...