I'd have to write a novel.
But -- in 25 words or less --:
UFOs are unlikely because of the distances involved, the laws of physics and the odds that advanced civilizations will fight themselves first before coming here.
That being said, I think you are correct in characterizing certain folks as EXTREME TYPE I Error-prone; they justify their position by pointing to people who are EXTREME TYPE II Error-prone.
The real truth is found somewhere other than clasifying personalities or hand-waving about survival value.
Cheers!
LOL.
THX.