Atom's music sounds like 80s music because he borrows heavily from it.
On A Society of People Named Elihu, snippets can be heard of
The theme from Beverly Hills Cop ("Axel F" by Harold Faltermeyer) is cleverly inserted in a cover of Nutrition by The Dead Milkmen on Making Love.
Atom covers Madonna's Open Your Heart in its entirety on Redefining Music, and if
that isn't 80s music, I don't know what is.