I've been observing debunkers on these NGs for at least two years now.
They've always raised my curiosity, especially the more empty-headed

variety

who don't even make an attempt at doing less than name calling, throwing
insults or making inappropriate responses to out-of-context, or snipped
posts to make some questionable point.

Summed up, debunkers are delusional.

<snip>

I'm not sure if I'd consider them delusional as I would scared out of their
wits. People tend to attack and try to discount those things that they fear
or can't understand. Acknowledging the existence aliens challenges some very
deeply held beliefs and threatens the very foundation on which many have
built their lives. Acknowledging the existence of aliens would force them to
change their worldview, their religious views, their political views, and
many other things they've simply accepted as "truth" from childhood. That
scares them and they will do whatever it takes to discredit those who bring
forward or who perpetuate that threat. Read a lot of the debunkers posts and
you'll see pure, unadulterated fear induced babbling.

Extended