"protest violence" is correct and usable in written English.
For example, you could use it in a sentence like, "The group has taken to the streets to protest violence against women."
In October, a vigil was held to protest violence in East Timor.
Several hundred people gathered in front of Cologne's cathedral late Tuesday to protest violence against women.
On Tuesday night, the police began firing tear gas in the park, where many demonstrators were as critical of the protest violence as of the police.
In a corner of the office sit stacks of hand-lettered placards that were made for a rally to protest violence against Guinean women.
Last Friday, as thousands gathered to protest, violence broke out (see picture, above) and three demonstrators were shot dead, apparently by members of the Republican Guard.
Earlier this month, hours after 2,000 people marched through Tijuana to protest violence, drug gangs shot 11 people dead, including a 14-year-old girl.
This song protests violence in Haiti and promotes democracy.
Youth radicalisation swept the world, culminating in explosive protests, violence and government crackdowns across Europe, Asia and North America.
"If we had participated in these protests, violence, killing and vandalism would have escalated," the group said.
That one was protesting violence against women, and many of the marchers had heard about it through social media or else had joined spontaneously.
With the memories of the protests, violence, and deaths that followed the 2005 general elections still fresh in the minds of many Ethiopians, the political climate prior to the 2010 elections was somewhat subdued, although not free of controversy.
