Complex sentence: Today the Comancheros have a strong Lebanese membership, which was not the case in the past, and were in the headlines in 2005 when they denounced the Cronulla Riots with Surfer gang the Bra Boys and also denounced retaliation attacks from Sydney's Lebanese community.
Split into simpler sentences: Today the Comancheros have a strong Lebanese membership, which was not the case in the past. The gang made headlines in 2005 when they denounced the Cronulla Riots with Surfer gang the Bra Boys and also denounced retaliation attacks from Sydney's Lebanese community.