The comparison is unhelpful. Whilst I disagree completely with medically unnecessary male infant circumcision, it's a very different thing which on the whole, is far less harmful and dangerous than FGM.
Additionally, male circumcision is complicated by the fact that there are relatively commonplace valid medical reasons for It to be carried out in childhood.
Male circumcision is also already culturally mainstream and completely unquestioned within communities which are very much larger and more diverse than the communities which practice FGM. Including some which are native to and have a long history within the UK.
Within the work on FGM, education and trying to create cultural shifts has been just as important as legislation and enforcement. And huge progress has been made, which mustn't be reversed.
Whereas we have not even begun to do the same work to spread the message within communities that male infant circumcision is harmful and wrong. Nothing remotely like that is being sanctioned or funded.
It is rash to jump from "this is completely sanctioned, legal and okay" to "this is now a crime" and there is no precedent example of this which is remotely similar, that I can think of.