Actually do it in a not broken way

app/helpers/home_helper.rb

@@ -6,7 +6,7 @@ module HomeHelper
     stdout, stderr, status = Open3.capture3('getent', 'passwd')
     return [] unless status.success?
     valid_users = stdout.split("\n").select { |user| user.start_with?(/\w/) }.map(&:split).map(&:first)
-    valid_users.map do |user|
+    return valid_users.map do |user|
       user.split(':')[0]
     end
   end
@@ -18,6 +18,8 @@ module HomeHelper
     end
   end
 
-  users = list_all_users
-  users_with_public_html(users)
+  def get_members
+    users = list_all_users
+    users_with_public_html(users)
+  end
 end

app/views/home/index.html.erb

@@ -7,7 +7,7 @@
 <div class="section">
   <p>Members</p>
   <ul class="members">
-    <% list_all_users.each do |user| %>
+    <% get_members.each do |user| %>
       <li><a href="/~<%= user %>"><%= user %></a></li>
     <% end %>
   </ul>