There are two subqueries, one for comments and one for posts, represented by (select c.creator_id from comment c ...) and (select p.creator_idfrom post p ...).
The WHERE conditions filter the results to include only comments/posts created by local users (u.local = true) who are not bot accounts (pe.bot_account = false).
What about votes? Do they count as activity?
No, only posts and comments, and not from bot accounts.
See here.
(select c.creator_id from comment c ...)and(select p.creator_id from post p ...).u.local = true) who are not bot accounts (pe.bot_account = false).