Conspiracy theories, just like any theories, are science too, they are part of the scientific process, you shouldn't discard them.
"Bunch of lunatics" sounds like ad hominem to me. Bad science again on your part.
"Honest scientists" is questionable in some cases (because of conflicts of interest) and honesty is sometimes irrelevant because they aren't infallible, they make mistakes too.
They give "simple explanations" that make sense **to you**. General relativity is not simple, at least for the average joe. Even most physicists don't fully understand it.
"Go ahead, prove earth is flat, moron", is not how you create constructive dialog.
Flatearthers are right at questioning things, they are wrong at making a cult out of it.
But attitudes like yours justify them for creating a cult, it's a self-defense mechanism, defense from attacks like the one you just did.