some anti-spam measures

app/controllers/users_controller.rb

@@ -98,6 +98,7 @@ class UsersController < ApplicationController
     @user    = User.find_by(user_params)
     return redirect_to(root_path, notice: 'That user does not exist.') if @user.nil?
     return redirect_to(root_path, notice: 'That user has chosen to hide their profile.') if @user.private_profile?
+    return redirect_to(root_path, notice: 'That user has had their profile hidden.') if @user.thredded_user_detail.moderation_state == 'blocked'
 
     @accent_color     = @user.favorite_page_type_color
     @accent_icon      = @user.favorite_page_type_icon

app/models/stream/share_comment.rb

@@ -1,7 +1,7 @@
 class ShareComment < ApplicationRecord
   acts_as_paranoid
 
-  belongs_to :user, optional: true
+  belongs_to :user, optional: true # now that we're auto-deleting this data, we can probably remove this constraint without db errors
   belongs_to :content_page_share
 
   def from_op?(share)

lib/tasks/daily.rake

@@ -3,6 +3,12 @@ namespace :daily do
   task clear_thredded_spam: :environment do
     Thredded::Post.where(moderation_state: "blocked").destroy_all
     Thredded::Topic.where(moderation_state: "blocked").destroy_all
+
+    blocked_user_ids = Thredded::UserDetail.where(moderation_state: "blocked").pluck(:user_id)
+
+    # Destroy all stream comments from blocked users and nil users
+    ShareComment.where(user_id: blocked_user_ids).destroy_all
+    ShareComment.where(user_id: nil).destroy_all
   end
 
   desc "Run end-of-day-analytics reporter"