It’s a complicated system, but that topic links to a topic about how to customize the inner content of email messages: Customize specific email templates. The idea is that you’re supposed to be able to customize the specific templates by selecting them from the admin / customize / email page.
For the User Posted template, you’ll see something like this:
%{header_instructions}
%{message}
%{context}
%{respond_instructions}
I think you could remove the bottom item from your screenshot by removing the %{context}
placeholder.