We are nowhere near advanced enough to say that life, complex or intelligent, doesn’t exist anywhere near us. There is no reason to believe an intelligent spacefaring race would make themselves so obviously detectable that us stupid primates could see them. And for non-intelligent life, we’ve been able to confirm mere thousands of planets. We have a very long way to go before we can start talking about the meaningfulness of a lack of life signatures in the atmosphere.
I itemized for the first time this year so I couldn’t use it, but I did fill it out completely as a comparison point to make sure itemizing was worth it. It was pretty painless, not very different from free filing through various other companies.