I personally think that the scientists and others who support SETI are nuts. Yes, I am using strong and disparaging language: nuts.
There are countless, yes countless species on earth that communicate with each other and we have no idea what these other species have to say. Since we know they communicate among themselves, it is reasonable to assume they have some intelligence. We just don't care enough to spend the kind of money and time we spend on SETI trying to understand our fellow earth creatures.
I have two particular favorites among intelligent fellow creatures: octopi and ravens. As far as I can tell many ravens and most octopi are more intelligent and have much more useful things to say to me than the scientists who support and work for SETI.