>>717169860 (OP)
same reason most straight porn prominently features a huge hard cock and the woman orgasming is a secondary concern while every single scene has a close up of the dude cumming. same reason all the weird neurotic interracial porn threads on this website are completely focused on the cocks while supposedly being for straight men to consume. same reason futafags get upset when you point out they are just using the female body attached to the giant cock as an excuse to jack off to a giant cock.
dudes like cocks, straight dudes, gay dudes, they just fucking love cocks. there's a lot of self insertion involved but only the most in denial retard can deny there's obviously something else going on, medical studies have shown straight men have involuntary blood flow reactions in their cocks when shown imagery of erect dicks - it could be some sort of sense of wanting to compete for access to sex or some sort of empathic mirroring response, but deep in the lizard brain on men there is a special fixation on juicy magnum dongs, even if we aren't actually wanting to fuck other men