I'm in general a very sceptical person, I expect the worst from the people in power. From the moon landing to 9/11. But, when good people starts to talk about lizards, flat earth or gigants i start to get worried. Are they just hyper alert / paranoid or are the deliberately trying to align sound scepticism with Looney toon conspiracy.
I agree with you that it's usually in powerful institutions best interest to lie.
but when someone's alternate explanation does not explain basic observational data,
and requires about a million people over a few hundred years to cooperate in a conspiracy,
it just isn't plausible.
it's just entertainment for them.