Well, if I I understood correctly that it is the only way for them to legally stay there - which I have no problems either. They either need to get work permit/visa or otherwise legalize their status there. They need to respect Netherlands laws and if they entered country illegally then they should be deported ( and I do not care if they muslim, jew or atheists)
As an immigrant myself who spend thousands of dollars in different fees, waited 3 years for visa to legally enter and live in Canada I have no sympathy for those who try to do it illegal way in any other countries. Respect the law and you will be respected as well.