The problem is, some people have a few ideas about islam, mainly picked up from the media and unpleasant anecdotes, and this affects how they see all muslim people, as we've seen on here. These people have very entrenched, rigid thinking, and seems to generally be quite angry.
So i want to add here, that the male or female that is politely declining to shake someones hand is part of a bigger picture. They will also most likely be the type of muslim who picks other peoples litter up from the road, moves other peoples obstructions off the pavement, tells the cashier when she has undercharged them, carries old ladies bags home when they arent going that way, give a £50 note in charity instead of keeping it when they find it somewhere, goes back into a shop to pay for a packet biscuits that they forgot in the bottom of their trolley even if they had got all the way home.
But what I am hearing in some of this thread is quite an over reaction to people who do not share our own cultural norms. We can afford to be generous, considerate to other people. Why would you assume the shaking hands thing has to do with respect? The shaking hands thing harms noone, it is vastly more important to the non hand shaker than it is to the shakee, why not just see it as an opportunity to understand more about people who are different?
There is a cultural group in my area who are in the habit of talking in large groups and taking over the whole pavement but not moving when you approach.
Of course this is rude and inconsiderate in English culture, I feel that for a moment as I approach. Instead of letting this fester into a frothing dislike of everything these people do (and its certainly not the only or even the most annoying or rude cultural issue), I remind myself that they are not being intentionaly rude and that for all I know it is the norm in their country.