Why do some folks think that if governments say that aliens are real, that must mean they are fake?

To me, it never made much sense to believe that they would be fake, if governments talk about the idea of alien life. Folks who despise the government, and rightly so, may look at it and think "Well, they've lied about everything else, they must be lying about this, too." And that wouldn't necessarily be true, either.

Many governments do flat out lie about stuff, but they tend to use a lot of half truths, which I think are arguably more dangerous than a lie. Because with a lie, you can at least dismiss it, but dismissing a half truth means you are also dismissing some of the truth, too.

Some may think that aliens are fake, because they plan to do a fake alien invasion in the future, and they may do that, but just because the invasion would be fake, doesn't mean aliens themselves are fake. Or that folks will say it's not actually aliens, but demons, which again, still doesn't make sense to say that, because aren't demons "aliens" by default if they didn't originate on Earth? Same for angels, devas and other otherworldly entities, which many legends speak of. Lots involve entities that clearly didn't originate on Earth.