The secret of GABHs is that they always come in TWO equal sized black holes, as the origin of primary Herbig Haro Systems, the start of star/galaxy formation.
Merger galaxies always show multiple dwaf galaxies around them and seem to become wasteful ( see below)
More GABHs around large galaxies means also more Dwarf galaxies.,
Star formation around large Black Holes has often stopped due to the plasma jet ripping of Herbig Haro systems. see