How can I exclude certain categories from the homepage?

support
2 
  {{ $p1 := where site.RegularPages "Type" "in" site.Params.mainSections }}
  {{ $p2 := where $p1 "Params.categories" "intersect" (slice "moments" "thinks") }}
  {{ $p := $p1 | complement $p2 }}

Think of the last line in terms of subtraction. $p = $p1 - $p2.