People who are bringing up the Westboro Baptist Church or the KKK need to stop. That argument is irrelevant. I personally agree that comparisons can be drawn, but the topic of this thread is about whether ISIS is legitimately Islam or not and Obama's statement on that. Deflecting this by saying 'oh well Christians do it too so maybe you should take a look in the mirror' is just a strawman. (Even if it's technically correct and the cons can't handle it)
As far as the OP goes, Obama got it wrong here IMO. 19 people were beheaded in Saudi Arabia, an established Muslim country, in the last month. The establishment of the caliphate is a central tenet to the Qur'an, and the slaughter of innocents in the qur'an is only forbidden under specific definitions of innocent (e.g. if you're older than 10 and not a muslim you're guilty). ISIS might be hardline islam but it's well within the parameters of the religion as defined in its holy books even if the majority of muslims do not subscribe to it. Obama didn't have much of a choice in this speech, lest he alienate a massive population and enable hatred towards innocent muslims. There needs to be a shift in viewpoint on how we view Islam, and there is a desperate need to recognize it for what it actually is, but this shift must be via a bottom up approach, a cultural shift in view, rather than top-down. It does seem however, that ISIS are doing all they can right now to propagate that viewpoint.