Well Paul I think you misread what is going on. In fact the taxpayers don't fund any SETI searches. The government used to until the late Sen. Proxmire could not see the sense in it and used his influence to stop funding. I could never understand how such a small amount, the sum our forces in Iraq spend during a coffee break, but with such a huge payback possible could be denied but it was. Of course the search for life outside the Earth is really the main theme of the probes to Mars, Saturn and other places in our solar system. How, or where we came from is a great mystery that is nearly within our grasp to understand.
No one in the SETI community is 'absolutely convinced we are not alone' or of anything else for that matter. We are scientists and the word 'absolute' sends shudders up and down our spine. We leave absolutes to people like you.
About the only complete agreement you will ever reached among a group of scientists is on the subject of 'absolute'. They know that they are merely scratching at the window of knowledge wishing to be allowed in to see more and to understand more.
I don't really understand your point about kidding ourselves about the drive for the search. The people I come in contact with consider this a quest not a means to an end like paying the bills or self aggrandizement. Of course they are human after all and have the standard set of foibles well all share but they really do love knowledge and are never happier than when discovering something new.
If you want to hear (and see) the people that I'm talking about in action play some of these videos. Warning - some of it is strong stuff.
http://thesciencenetwork.org/BeyondBelief/