Are not all such laws subservient to French Law?
You cannot use justice to fight the societal norm, it can only be used against exceptional violations of the law. You talked about a few high-profile people speaking in public, the law can of curse be used against them, but not against half of your suburbs.
The the norm in Muslim cities is that brown people have a duty to be Muslims, period. It does not come from a few individuals, it is diffuse, it is the societal norm. And this is why brown people face a multitude of pressures, intimidation, discrimination and assaults against themselves and their relatives. The violations are too many and too ordinary to be fought with justice, and members of the sect have been indoctrinated to not talk against the sect.
For now this almost only concerns brown guys (and Jews and gays - but they already left - and critics of Islam, and women wearing "too sexy" clothes). With time it will concern everyone.
UK law should have primacy in the UK.
It does not in your suburbs. There, brown people have a duty to be Muslims, and many offenses are unlawfully punished by violence, such as homosexuality, Judaism, etc.
There, we get into ideology. We have to battle ideology just as we had to fight other pernicious ideology.
This is what politics are about!
Every single one of our laws is an usage of force (police) in service of our ideology. Prohibition of murder? Ideology.
You want leftist values to prevail over rightist values. I want French values to prevail over Islamic values. Mind you, I have the right to want a French France, this is democracy, swallow it.
After Charlie they convinced 40% of voters that blasphemy should be banned, so they already enjoy some support among the voters.
And nearly four out of five of them want to ban blasphemy, so this is a major electoral question for them, one that can make the difference between a national victory or defeat. Of course it will happen
And you know what? They do not even need to change the law. They just need a few judges to start considering that blasphemy is hate crime. This legal trick could not work in UK, but this would in France, Germany and most of Europe.