ICE agents wear masks primarily to protect their identities and their families from doxing and threats, not specifically because of 'the left's violent ways.'
The lefts violent ways is why ICE agents have to wear masks.

Ice chief says he will continue to allow agents to wear masks during arrest raids - US immigration | The Guardian
Source: theguardian.com
Key Evidence
ICE leadership acknowledges mask use is due to threats and doxing of agents' families.
theguardian.comtheguardian.comIce chief says he will continue to allow agents to wear masks during arrest...
thehill.comthehill.comBorder czar: ‘I don’t particularly like masks, but the agents need the mask’
Several states have legislated against mask-wearing by ICE agents citing transparency and accountability concerns.
nytimes.comnytimes.comICE Agents Can’t Wear Masks Under Bill Passed in California
apnews.comapnews.comCalifornia lawmakers pass bill to bar ICE agents from wearing masks
Media coverage highlights debates over safety versus public trust but does not attribute mask use directly to violence from any political group.
nytimes.comnytimes.comICE Agents Are Wearing Masks. Is That Un-American?
reuters.comreuters.comLos Angeles ICE raids fuel controversy over masked agents
What the Evidence Shows
The claim that ICE agents wear masks due to 'the left's violent ways' oversimplifies and misattributes the reasons behind this practice. Multiple sources indicate that ICE agents have increasingly worn masks during raids and arrests to conceal their identities for safety reasons. According to the ICE chief and the Border Czar, agents' families have been doxed and threatened, which has led to concerns about personal safety.theguardian.comtheguardian.comIce chief says he will continue to allow agents to wear masks during arrest...
thehill.comthehill.comBorder czar: ‘I don’t particularly like masks, but the agents need the mask’
This protective measure is controversial and has sparked political debate, with some states passing laws to ban mask-wearing by law enforcement officers during public interactions.nytimes.comnytimes.comICE Agents Can’t Wear Masks Under Bill Passed in California The controversy includes concerns about intimidation tactics and the potential for impersonation by criminals.
pbs.orgpbs.orgRise of ICE agents wearing masks creates opportunity for imposters to conduct...+4 more
However, none of the sources directly link mask-wearing to violence specifically attributed to 'the left. ' Instead, the rationale centers on threats against agents and their families from various sources. The political framing of 'the left's violent ways' is not supported by the evidence presented in these reports.