It's more complicated than that. Sheik Tamim is a comparatively young ruler in a society where age matters. There have been a string of quiet articles In the Western press ever since he came to the throne about how difficult it is for him to wield control over all aspects of the government and the wealthier families in the society (which is where the money for ISIL is actually coming from).
This development is potentially just the thing that the Sheik needs to finally exert power over these people. Or it could all go hideously wrong for all Qataris.
Likewise the leaks that have stimulated this reaction are a convenient public justification for UAE, Saudi Arabia, etc. I suspect they've been itching to do this for a long time, and now they can.