It would appear that any attempt to reject or ban customs or practices of radical Islam will spark outrage among Islamic extremists and spark increased recruits to ISIS. It is a religious and cultural war where any attempt to prohibit certain beliefs or ban customs is not tolerated by either group.
France’s Prime Minister has backed the banning of burkini swimsuits, which will spark increased recruitment to ISIS. The terrorist organization will use this as propaganda to show how the west is antagonistic against Muslims. The banning of religious gear does not help the fight against extremists, who will still meet in secret.
Many women prefer the modesty afforded them by burkini swimsuits and freely choose to wear these garments. They do not feel they are enslaved - they simply prefer to not display their bare flesh in front of strangers. Banning this mode of dress is likely to enrage young, vulnerable men and women who could join ISIS as they are made to feel unwelcome in a society that rejects their values.
While the decision of France's Prime Minister to back he banning of burkini swimsuits may be met with criticism, political unrest or protest, I do not believe that it will spark increased recruits to ISIS. An event such as this will obviously be met with protest and outrage among certain circles, I think it would be an unfair reach to say it would instigate radicalization and encourage people to side with a terrorist group.