I don't need to defend Islam against ISIS any more than I need to defend Islam against a random guy barking at people down the street. ISIS have no authority over Islam, none what so ever. You are forgetting two very basic things:
Islam (mainstream) is a decentralized religion that categorically refuses central religious authority over the religion. There is no "ruling church" or "pope figure". And therefore the actions of any muslim or a group of muslims is binding and representative to no one other than themselves. Why would I need to "defend" Islam, a huge religion followed by roughly a quarter of all human beings from a random group in Syria that holds exactly zero authority over Islam and muslims and anyone who is not part of them.
How tiny ISIS is and how much the constant media reporting inflates it and causes the public perception to shift. The CIA says there are 10,000 to 20,000 fighters. Russia says they are 70,000. Forget that and lets REALLY inflate their numbers ten times over and say there are 200,000 of them (and that's an incredibly imaginative stretch). According to muslimpopulation.com there are 2.08 BILLION muslims worldwide (2014) and growing. So what percentage does that make isis among muslims? Even with the super ultra inflated ten folds number of ISIS that puts them at 0.00961% of muslims. Why on earth are they made the representitives of islams but not the other 99.991% ? Let me paint you a picture. I did this using excel, surface area of the circle represents the number. Black circle represents the number of muslims, the small circle represents the ten folds inflated ISIS numbers. It was invisible so I made it black over white background to make it possible to see it and added a red arrow pointing at it so you want miss it. Now tell me, how much is the dot getting media attention, and how much attention is given the the circle? why would I need to defend islam against a pixel? The systematic dehumanization of the circle for the benefit of the pixel is what's really messed up, the circle is just fine.
