Free and open debate is one of the hallmarks of a secular society. Freedom of thought and speech is vital. The utterly vile Westboro baptist for example - hideous though they are, they cannot be subject to government censure for their views. Similarly, this group - utterly awful but they have a right to gather and discuss.
However... Free speech does NOT mean you get to say whatever you want with no repercussions. The government cannot stop you, but if for example, a load of hells Angels and gay activists show up at a Westboro protest to shield the families, then hey, that's free speech too. So is a bunch of Femen activists turning up at a debate on wife beating.
Femen had a right to peacefully protest this gathering. The gathering had a right to go ahead. The ONLY way we are going to tackle hate, misogyny, racism etc is to tackle it head on through peaceful counter discussion, not through banning things.
hackermum above said something I passionately agree with. religion does not get a free pass we MUST be free to criticise, mock and refute any aspect of any ideology we like. Too often people are putting down debate by yelling "islamphobia" to silence people.
Let me be perfectly plain - there is a huge difference between hating/discriminating against a person due to their religion (wrong, illegal) and disliking/arguing against an ideology that a person holds (perfectly ok.) it is not islamophobic to say ' hmmm now, I'm unhappy with how your religion treats gays/women" just as it's not anti Semitic to enquire why the Israeli army was using white phosphorus shells in gaza.
By blindly yelling "xophobia!" We stifle debate. We need to make sure the ideal is a secular society where individuals are not discriminated against based on religion, but those religious idelogies are not immune from scrutiny. Otherwise we are fucking doomed.