Is it possible that their arguments haven't been noticed to be debunked? These are apparently the authors:
> The book was written by married couple Kelly Weinersmith, an adjunct professor at Rice University in the BioSciences Department, and Zach Weinersmith, a cartoonist known for the webcomic Saturday Morning Breakfast Cereal.
Its a good read. I'd encourage you to read it and come to your own conclusion on your question. Personally, they earned my trust but other members of our book club did not agree.
Space is very very unforgiving and they ultimately conclude humanity is better served focusing our resources here on earth first. But the Trekkies have a tough time with that answer because its a bit of a let down.