Of course we should question what we are told, but you have to trust some sources to get by in life. I don't believe that all politicians/reporters/scientists are out to lie to us, and it may just be a small minority who do really bad stuff. There are some in power who want to destroy our trust in any authority, or at least so my own conspiracy theory goes.
As for flat-earthers, I've given up on talking to them as it's a waste of my time.
Agreed. Though I'd suggest that the audience for this kind of thing does trust some sources - they're just bad sources. It's the breakdown of trust in institutions that is part of the reason for the greater proliferation of this kind of thing - which I haven't yet gotten into. However, one of those institutions may be the granddaddy of all conspiracy theories :) -- and I'll get into that too.