Complex sentence: Whatever their criticisms of what the IRSP and INLA had become, the IPLO were worse, their attacks on the IRSM left many in Belfast's nationalist communities living in terror and many volunteers dead on both sides.
Split into simpler sentences: Whatever their criticisms of what the IRSP and INLA had become, the IPLO were worse. Their attacks on the IRSM left many in Belfast's nationalist communities living in terror and many volunteers dead on both sides.