For Wallace the conditions required for life (much less the complex diversity of life found on earth) were so many that they make the likelihood of extraterrestrial life highly improbable.
Darwinian theory allowed a framework and easy fit into which Hitler’s Nazis could cast their racial program as both scientific and even inexorable.
Why must Wallace suffer the insults of George Beccaloni?
Why develop speaking or extraordinary learning capacities or complex social units when sheer stealth or speed or agility would have sufficed?
Darwin came to his ideas not by the evidence but by an a priori ideology that dictated methodological naturalism and philosophical materialism.