Having spent 30+ years in argumentation with Conservatives, Objectivists, Right Wing Libertarians, and 'All that Crew' my tolerance for their vacuousness has evaporated.  By "argumentation" I specifically mean "the use of effective and correct reasoning in ethical dialectic."  Offsetting this is my interest in constructing, somehow, a body of work refuting the Right's ideologies.

As to

The question is, is the ET strategy to preach to the converted or to teach and influence Mainstream opinion?

My answer is, "Yes."

Both intellectual validation and persuasion are worthy goals and can be carried on simultaneously.  How individuals approach those tasks - should they have an interest - is, of course, up to them.  

By validation I mean the psycho-epistemic realization, "Hey!  I'm not alone AND my ideas have intellectual respectibility."

By "persuasion" I mean someone accepting a statement, proposition, or conclusion due to acceptance of the reasons supporting the statement, proposition, or conclusion.  I have zero interest in establishing the 'The Left Church of ATinNM: Semiotic, Epistemological, & Post-Modernist."

From all this I don't give a damn about 'Terry' lurking or engaging as long as 'he' obeys the norms of ET.  Repeating myself, my basic tenet is posting on ET is a Privilege, not a Right.  
 

She believed in nothing; only her skepticism kept her from being an atheist. -- Jean-Paul Sartre