I run SETI@home because I want to contribute to the biggest discovery in whole history
ET intelligence is statistically possible. So, the real question to my point of view is why we haven't found them yet, or why "they" haven't given us a sign of their existence.
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.