Many of your concerns were addressed by the author in the comments section: http://richardkulisz.blogspot.com/2007/04/aliens-dont-exist....
He completely ignores that humans actually took many tens of millions of years to evolve from scratch not from existing life forms.
Kulisz responded:
The point is that it didn't have to. Nothing in the universe prevented a technological civilization from arising 8 billion years ago. And certainly not 65 million years ago back when the dinosaurs ruled.