If you are not clear about the issue with Islam then consider the situation with JWs.
Many people who perhaps know a Witness but have never engaged with the organisation would be quite prepared to say that Witnesses are nice people. They are law-abiding, don't cause a fuss, peaceable and so on.
What they fail to recognise, however, is that every Witness, other than a very small minority of those on the edge, subscribes to a whole set of fundamental norms that are built into their core perception of how the world should be organised from a moral and theological perspective. These norms do not align with what would be considered modern, progressive attitudes to human interaction. For example:
Women are in subjection to men and have been conditioned to willingly accept the situation as their God given role. Non Witnesses are condemned to the prospect of destruction at a global war yet this threat is publicly downplayed. Those who fail to meet the standards of the organisation or choose to formally leave are completely shunned yet this behaviour is blamed on the person as something that they have brought on themselves and ultimately will be good for them. Homosexual relationships are completely unacceptable yet this again is publicly downplayed to try and avoid claims of homophobia.
The same is true of Islam. Of course most Muslims we are likely to meet in our day to day lives are not violent Jihadists however the vast majority essentially subscribe to a set of moral and cultural norms that do not encourage tolerance and diversity.
What is worse is that it's highly unlikely that any Witness will ever resort to violence and terror in support of their brand of Christianity however this is absolutely not the case with Islam.
It's good to see some Muslims taking a stand, for example by their support of public events related to the Westminster attack last week however there really does need to be much more done from the inside out to bring real reform.
