Lemmy can only follow communities, not users. Otherwise it would require a whole new UI and other major changes. Doesnt make much sense when you can create a second account on Mastodon or one of many other platforms which already implement user following much better.
@nutomic@EnglishMobster wouldn't it be possible to follow a mastodon user and view them as some kind of single-person community? This would allow Lemmy-users to view those on their feed