Hard to Imagine what drives some SETI critics. It's costing them nothing...No one will make any monetary gain from its operation, so what's the beef??? Some rather thoughtful, Imaginative knowledge seeking individuals, doing what man has done since he climbed down out of the trees.
The same anti SETI brigade, were they screaming/whinging about the costs etc of the "useless"endeavours of putting man on the Moon??The Space Shuttle???, The ISS???, the HST??? the Mars probes?? Voyager?, Pioneer?? etc etc etc.
Were they crying re how much bang for their buck??
SETI is an Innovative project to extend our understanding of the Universe and our place within it.
The "more bang for your buck" is never the prime reason for science. That reason is furthering our knowledge and place within this Universe. This cannot be measured directly by invoking the " bag for your buck" concept.
The future will see an eventual return to the Moon, probably manned Asteroid exploration, and of course manned Mars missions.
I hope that the same screams when these futuristic projects finally take off, are well and truly stifled underfoot.
Space exploration and research is our destiny, it is the final frontier [as corny as that may sound] and man will continue to probe, explore and learn from this new environment.
SETI is part and parcel of this effort.
We search the stars for life, and for the same reasons we climbed Mnt Everest, explored Antarctica, because they are there, and because its our very nature to explore, risk life maybe, gain knowledge most certainly, and of course the adrenalin rush and the glory.
So to our science spoilers out there...Let it go, it's costing you nothing, and even though the longest of long shots, the return will be breath-takingly humanity changing, and for the better I might add.
And of course any positive results would hasten efforts to discover the most efficient path to the stars.
Orginisations such as Tau Zero, and 100 Year Star Ship Co, will have a head start.
*end of rant*