I think it’s incredibly stupid to assume there is no other forms of life in other universes and galaxies.
I agree..
There is an enormous differences between an assumption and creating a testable hypothesis on what conditions MIGHT lead to lack of other life forms. In that it would be stupid to be dogmatic about the idea in either direction, I agree with you.
When Alfred Wegener espoused the theory of Continental Drift in 1912, he built upon observations noticed by mapmakers and scientists since the late 16th Century. Because he could not explain a causative mechanism and because he was a meteorologist rather than a geologist, dogmatic scientists ignored the obvious fit of Africa and South America. It took decades to develop the Plate Tectonics theory that underlies the process and validates Wegener.
I can cite other examples but in this single known universe that we live in, I hesitate to make any dogmatic statement about life elsewhere. That being said, I'd love to have a universe with Vulcans, Wookies and other non-human life forms. That would really add spice to the life of everyone!