Probably so unhinged individuals don't show up at their homes and attack their families for performing unpopular law enforcement functions?
Interesting that record deportations under the Obama administration didn't spur such reactions to immigration enforcement at the time. Has there been any change in behavior by officials?
Setting aside their lawlessness, it sounds like we agree they are unidentifiable, meaning their identity is a secret. So they are a secret police. And you support that for some reason, maybe because you haven't read a single history book.