I'm not really sure how you can read the history of the organization and come up with that. al-Tawid was founded at around the same time as al Qaeda (within a few years), and they merged to become al Qaeda in Iraq and then ISIS/ISIL.

In some ways the person I was responding to was right because, between Osama and al Zarqawi, Osama was definitely the moderate. But you're talking about wanting to kill everyone who isn't a muslim vs. everyone who isn't sunni muslim.

The idea that ISIS is something fundamentally different is driven by the media. It's sort of how DARE tries to scare parents by saying "This generation is smoking some really crazy stuff you're not familiar with!"