Achieved almost entirely by fighting through normal means, guns and such so I hardly see the relevant. Suicide bombing kills a vanishing small number of people. IED's are an actual threat.

Their original goal as rebels was to remove a central government and now they're fighting a war of genocide against other rebel factions. I wonder how they would have responded if you'd told them at the start that a short while later they'd be slaughtering fellow muslims in direct opposition to their holy book.