First off the idea that police should be allowed to wear masks because their job is dangerous is ridiculous. Not even worth considering. Do something else then.
Second, if ice agents are allowed to wear masks it encourages people to impersonate them.
Authorities in three states have made arrests in connection with individuals impersonating Immigration and Customs Enforcement (ICE) officers, as tensions rise amid a nationwide immigration crackdown.
amp.cnn.com
Third, if an ice agent overreaches or kills someone, and is masked, they are much harder to identify and hold accountable. You can’t expect to be in a position of authority, arresting people, using force, while simultaneously having zero accountability. And no, badge numbers are not enough.