No, the SSDF limited its operation mostly to within its own tribal territory. Most controversial was the infighting that occured between the differing factions, but that was very much a more political conflict, or as political as Somalia can get, and like the conflict within the USC mostly harmed its own tribal people.
On the question on why they still seem to support SL, its the curse of the small guy. Vast majority of Gadabuursi in the west are staunch unionist, but if you're in SL talking about unionism enough times the cops will show up at your door, and believe me you do not want that. In the end people want to live a quite life with as little distractions. It's not like SL is an apartheid state, so aslong as peace is still there and unionismisnt protected by Somalia, people will do what is neccesary to survive.