I don't know if that's what's going on. I suspect some haven't really sat down to think about what exactly they believe and why. Most seem to be parroting various mantras I've seen expressed on Twitter and Reddit without having thought about the implications of what they're parroting.
There's still a lot of unfounded blank-slatism and autism (in the sense of inability to empathize) in our educated society, and proudly on display here on HN.
It's effectively impossible to get someone with an IQ of 130 to have empathy for someone with an IQ of 95. They just need to work harder, they just need to have better teachers, they just need to stop watching so much television, they just need to get better nutrition, ad nauseum.
Imagine the ego crush that would occur if a 130 IQ true-believer in human equality is faced with the prospect that their intellectual success is due to winning a genetic lottery, not due to their hard work and proper life choices.
Of course they're going to deny the reality of hardwired cognitive horsepower.
To do otherwise is to deny how much better they are than you.
I struggled with basketball in PE. The teacher said that maybe it just wasn't for me, and had me sit on the bench for the rest of the basketball unit. For some reason they didn’t force EVERYONE to sit for six weeks cause I couldn’t basketball. Now explain to me how math differs.