The idea that a kid born in Moscow can be a religious fanatic or an “islamist” that beheads people over Mohammed cartoons is ludicrous. These are people who have been completely secular for over a century. There’s something else going on.
It’s a completely different question why France had to drag these particular Russians over. The Moscow Chechens are wealthy and universally feared in the city. They are under Putin’s protection. There’s a bunch of famous gay nightclubs owned by Moscow Chechens. Why it was so crucial to drag them over to France is a mystery.