The easiest solution to the paradox is that the "filter" is a hard limit to what technological development is capable of. If we can't, even in the best scenario, overcome the barriers needed for serious interstellar travel or communication, then we're probably the norm.

It's much easier for me to believe that humanity's imagination has a hard cap on what it's capable of than it is for me to imagine that a mightaswellbe-infinite number of species all mutually share a philosophical attitude that borders on psychopathy.