Yes. That’s how it works.

I don't agree.

Concluding that the absence of evidence constitutes evidence of absence sounds like the logical fallacy of argument out of ignorance to me. It's not an accusation of someone being ignorant, but a term used in the field of logic.

The lack of (what would generally be accepted as) evidence doesn't prove anything beyond that we've found no evidence. But that absolutely impacts what assumptions we should make about a question that so far have no evidence either for or against.

Claim a thing, prove a thing- or be dismissed.

Everybody's free to chose who they dismiss and not and what parts of testimonies. We seemingly subscribe to two different methods of looking at the topic, I'm happy using mine until something better comes along.

Is it that anyone can say something and it’s true for you regardless of evidence?

You're always free to try to claim something and see how I react. From our interactions so far I'd say I rather try to analyze claims through the intellectual tools humanity have refined over hundreds of years to the best of my ability, and more often than not I find claims insufficiently substantiated. Like your claim of lack of proof being proof that nothing happened.

I hope I've shown you a different way of analyzing unknowns, and if not - We'll know for sure either when we meet little green men for the first time or humanity have searched every nook and cranny of the universe and found nothing.