Because NOBODY shows any EVIDENCE, so, it is POSSIBLE that your previous decision was not the right one.
What if those who you think were Right...are Wrong and consequently, those you think were Wrong are Right ?
Impossible? No, I don't think it's impossible at all.
Disbelievers become Believers and the opposite is also true.
I know you read a lot about Aliens: (good aliens, bad aliens, hundreds of aliens, ugly aliens, beautiful aliens, aggressive aliens, compassionate aliens, and so on, but please remember this: you read ABOUT aliens, but the aliens, the "real thing" is NEVER THERE.
Some day perhaps, but until this moment, the only thing you have is talk, talk, talk...contradictory talk.
Who is Right and who is Wrong? You don't know. It's not a rational option. You just have Faith in this Ufologist or that one.
Do some googling please, and watch the Chaos. Contradictory statements, Info-Wars, accusations, hate.
Discord rules the UFO-fans Culture.
What can you do?
There is one thing you can't do:
You cannot ask the Aliens about Truth because our "ET brothers and sisters" are NEVER THERE.
Perhaps these words will help you to choose between "right" and "wrong", or you will understand what you attitude should be:
Just DO NOT CHOOSE and watch the Show with detachment. Enjoy the Game from outside.