I usually judge how “wrong” something is by how harmful it is, and how “good” a law or idea is based on how much harm can be reduced by it; based on that male circumcision doesn’t quite compare to FGM.
We have several forms of ritual female genital mutilation under the umbrella term Female Genital Mutilation. Under these broad terms, FGM has substantial weight and is rightfully and broadly condemned. We could just as easily do the same with ritual male genital mutilation, though. We could include subincision and other forms of ritual male genital mutilation and put them under the umbrella term Male Genital Mutilation. If we are going to insist on having a broad definition for one, let's have the same for the other.
When we compare like for like fairly in this way, the analogy is no longer even an analogy. We are literally just dividing genital mutilation into two gender categories, a simple division between the gender of the victim, both categories containing extreme and lasting abuse. In fact, why the binary gender divide at all? It seems like an arbitrary and unimportant distinction to me. It's all barbarism to me. All condemned by me. British law should transcend the two-class gender divide of foreign nations and not kowtow to cultural and moral relativism. Genital mutilation of children is indefensible. It's obscene even in lesser forms.
You could argue that gender categorisation is useful for focussed and specialised activism, outreach groups, etc. But beyond that, we should be operating on sound principle. The law should be gender and culture blind as far as it is possible. This would not restrict activism, it would empower it. Relativism can be exploited. It can be a rationalisation for inaction. It can manifest as favouritism and discrimination.
I also don’t think much good will come from criminalizing infant male circumcision; Muslims are NOT going to give it up and I already know of a few girls who’ve been “cut” overseas despite the fact that FGM is only mildly endorsed by Islam. Male circumcision is a lot more entrenched and it’ll just move from a safe, sanitary hospital environment to razor blades, kitchen knives and Third World countries, and consequently much higher rates of death and complications.
That something is widespread or entrenched is not a good reason to not push for changes in law or enforcement of existing law. You could say that about so many things too. From petty driving offences to domestic abuse. If it was criminalised, Muslims would HAVE to give it up or face the law. It wouldn't vanish overnight, but it would have a form of chilling effect that would be the beginning of lasting change.
And the reason why girls have been taken abroad and cut is because they can be. Because authorities are too morally craven to enforce existing laws, to push for convictions, to install simple methods of detection, routine check ups and focussed education in problem demographics, and so on. It's not the simplest thing in the world. It's certainly harder than making excuses and doing nothing. It would require action effort and funding. But it's not rocket surgery either. It's completely doable.