This, for starters, is revolting. Women in Sudan being given lashes (not the mascara kind) for wearing trousers in public. Now the issue is that the lashes were given under Sharia law which is only supposed to apply to Muslims - the women were mostly Christian or animist.
Of course the notion that non-followers of a religion should adhere to it's laws is stupid - but still one I hear a great deal in the UK on issues like abortion and gay marriage. But more importantly:
1) Who exactly gets to decide whether a woman in Muslim or not? Is she herself genuinely entitled to a free choice on the matter? I strongly doubt it.
2) Where is the righteousness in following the laws of your religion out of fear of being flogged rather than out of personal piety?
3) Assuming the Muslim community wishes others to follow Islam - how exactly do they think this is going to attract new converts?