gistfile1.txt

function jetpackme_filter_exclude_category( $filters ) {
  $filters[] = array( 'not' => array(
    'terms' => array( 'category.slug' =>
      array( 'donotshow', 'events' )
    )
  ) );
  return $filters;
}

add_filter(
  'jetpack_relatedposts_filter_filters',
  'jetpackme_filter_exclude_category'
);