Actually they might be following you
It’s just that you have so many users whose usernames starts with an S that said user shown might’ve been buried since they have less points than the other users
Perhaps try typing in more of the letters in the username
There are a few reasons
1. Invited link was involved
2. You followed them at some point and
They memechatted you
3. They followed you at some point and you memechatted them