No idea what Mo Farahs wedding photo has to do with anything Though.
Bare shoulders. Head not covered. That's transgressive in many other ways apart from her not being (we presume, but it seems a reasonable assumption) mutilated as a child. Has the Somali community in the UK disowned him for these crimes? No, they have not. Are there probably a small hardcore who think him a traitor for "marrying out"? Almost certainly. So I don't think it is "Massive parts of communities", because aside from anything else a commonly cited reason for coming to the UK is precisely to escape these cultural issues.
That's one of the worst things that our engagement with "community leaders" has caused. People come to the UK from country X seeking a new life, one free of the pressures of conformity to cultural practices. Our response is to seek out the most conservative elements and present their views as normative.
Think about Muslims you know, for example. Now, think about "Muslim representatives" who are picked by government or the BBC to speak on "issues". I'll bet that the Muslims you know are less bearded, less male, younger and if female less veiled than the people presented in the media and in government as normative. That makes it much harder for progressive elements, because they are both blamed for things they don't believe in ("all Muslims...", "all Somalis..." on FGM, terrorism, etc) and if young and disempowered conservatives are presented to them as models to aspire to.
If there's discussion in the media about, for example, same sex marriage, headbangers like Andrea Minichiello Williams are not presented as being representatives of the white "community", and not even of being representative of Christians, and very few Christians actually share her lunatic views. She is openly mocked, and any debate involving her will have open-hearted Christians from accepting traditions as well.
When the topic at hand is something to do with non-Christian communities, the most appalling reactionaries are sought out and presented as though their views are mainstream (one might mention Anjem Choudary in this, but he's hardly the only one). Young people, perhaps reacting to their parents' conservatism, are only shown conservative models. It's like Richard Dawkins' trick of re-labelling Christianity as consisting only of hardline lunatics, and then dismissing anyone less unreasonable as "not a real Christian".
The vast majority of Somalis in the UK, like the vast majority of Muslims, want nothing of FGM, ISIS and book burning. A tiny minority do. It helps no-one, except that small minority, to paint them as normative. It makes us helpless (what can we do?), it makes us worry about the wrong things (how will uncut women find husbands? -- which leads to the appalling ideas of "minor" FGM being somehow doing them a favour) and it makes us give up the tools we have.
It is essentialising to believe that most people in any particular group share distasteful ideas, unless you have strong evidence to show it is true.