A porch is still on the property, and remains distinct from public space. That he is physically "outside" is not by itself enough to be considered public.
Also, you apparently still haven't read the police report, which appears to indicate two things:
-the "crowd" was already outside before Gatea stepped onto his porch, so you're just guessing when you say his shouting drew a crowd
-the language in the report does not give any indication that Gate's was deliberately attempting to incite the crowd
So your "checks" seem to be complete conjecture, which, as your own link points out, the prosecution would need to prove, something which they apparently were not comfortable doing, for whatever reason.
Also, you apparently still haven't read the police report, which appears to indicate two things:
-the "crowd" was already outside before Gatea stepped onto his porch, so you're just guessing when you say his shouting drew a crowd
-the language in the report does not give any indication that Gate's was deliberately attempting to incite the crowd
So your "checks" seem to be complete conjecture, which, as your own link points out, the prosecution would need to prove, something which they apparently were not comfortable doing, for whatever reason.