These are dark times of the panIslamic world. You seem to have ummah perspective but the panIslamic world is split along the lines of nation states. These nation states compete with each other and some have conflicts between them. Some supported Soviet Union and some supported USA in the Cold War and fought each other. Iran - Iraq War is notable example. US supported Iraq in this war but liberated Kuwait from Iraq later. US also supported Afghanistan when it was occupied by Soviet Union but the so-called Mujahideen turned out be just as bad as the Soviet Union. One of these groups created Al-Qaeda Network and was involved in terrorist incidents around the world including 9/11. This group motivated US to destroy it and settle scores with Iraq and others as well. Ummah believers created ISIL in response instead of helping other Muslims. This is our reality. Corruption and mischief everywhere.
Muslims are split on nationalistic, political, and religiopolitical grounds around the world. Muslims have killed other Muslims on these grounds, still do.