The problem with that statement, is that those supposedly 'secular' authorities, weren't 'secualr', but very 'religious', such as Spain, Portugal, England, Germany, Geneva, France (before it bcame secular) and the north countries (Sweden, Norway, Finland), as each were Roman Catholic at the higest levels of government, such as Ferdinand and Isabella of Spain, 'Bloody' Mary, even the German Emperor, whose aunt was the first wife (Catherine of Aragon, also Catholic) of Henry VIII (who himself was a staunch Catholic, and merely had divorce issues).
The St. Bartholomew's Day massacre was carried out by Catholics, even as a Catholic author and historian, Lord Acton, and others have stated. So the whole ideology, that such was carried out by 'secular' authorities is revisionist history, and not accurate all. In other words, those states (political entities) were so thoroughly Catholic in principle, they were simply carrying out the papacy's directives, and believed it to be proper, see also Frederick II at Padua.