Thallish and crinklesock are weird, I agree. It's probably part of their vocabulary and you'd have to lurk for a while to understand those. But the rest?
alpine = alpine phenotype or "alpine race"
neothenized = with neotenous features
The title is the strangest part, but it's what makes me believe that the forum is just an offshoot of a bigger one. It sounds like an inside joke of sorts. It's not a thing per se, but I think what they meant is that neanderthals (they have those pictures in the banner), and people with neanderthal dna now (europeans) are "altruistic", which, lmao; and they need to protect the "altruistic" or neanderthal genes. It's white supremacist autism.