That's been tried before during the 4th Crusade. They'll employ taqqiya and continue practicing Islam in private, wait it out for a generation or two (if that), and once it appears that the nation has begun forgetting their history, those savages will have continued to expand through their birthrates, while continuing to practice Islam in secret, so after about 40-50 yrs, they suddenly start showing their true colors and intentions.

This isn't even about "radical" Islam. Islam itself is a radical and hyper violent ideology of fear, hatred, and extreme oppression through violence. It's the only Abrahamic religion created from and through hatred and violence toward all others. Muhammed admitted it himself.